that I shall prove is That the gradual heating and cooling of these so extended bodies does reduce the parts of the Glass to a looser and softer temper And this I found by heating them and keeping them for a prety while very red hot in a fire for thereby I found them to grow a little lighter and the small Stems to be very easily broken and snapt any where without at all making the drop fly whereas before they were so exceeding hard that they could not be broken without much difficulty and upon their breaking the whole drop would fly in pieces with very great violence The Reason of which last seems to be that the leisurely heating and cooling of the parts does not only wast some part of the Glass it self but ranges all the parts into a better order and gives each Particle an opportunity of relaxing its self and consequently neither will the parts hold so strongly together as before nor be so difficult to be broken The parts now more easily yielding nor will the other parts fly in pieces because the parts have no bended Springs The relaxation also in the temper of hardned Steel and hammered Metals by nealing them in the fire seems to proceed from much the same cause For both by quenching suddenly such Metals as have vitrified parts interspers'd as Steel has and by hammering of other kinds that do not so much abound with them as Silver Brass c. the parts are put into and detained in a bended posture which by the agitation of Heat are shaken and loosened and suffered to unbend themselves Observ. VIII Of the fiery Sparks struck from a Flint or Steel Schem V And the First was of a pretty big Ball fastened on to the end of a small sliver of Iron which Compositum seemed to be nothing else but a long thin chip of Iron one of whose ends was melted into a small round Globul the other end remaining unmelted and irregular and perfectly Iron The Second Instance was not less remarkable then the First for I found when a Spark went out nothing but a very small thin long sliver of Iron or Steel unmelted at either end So that it seems that some of these Sparks are the slivers or chips of the Iron vitrified Others are only the slivers melted into Balls without vitrification And the third kind are only small slivers of the Iron made red-hot with the violence of the stroke given on the Steel by the Flint He that shall diligently examine the Phaenomena of this Experiment will I doubt not find cause to believe that the reason I have heretofore given of it is the true and genuine cause of it namely That the Spark appearing so bright in the falling is nothing else but a small piece of the Steel or Flint but most commonly of the Steel which by the violence of the stroke is at the same time sever'd and heatt red-hot and that sometimes to such a degree as to make it melt together into a small Globule of Steel and sometimes also is that heat so very intense as further to melt it and vitrifie it but many times the heat is so gentle as to be able to make the sliver only red hot which notwithstanding falling upon the tinder that is only a very curious small Coal made of the small threads of Linnen burnt to coals and char'd it easily sets it on fire Nor will any part of this Hypothesis seem strange to him that considers First that either hammering or filing or otherwise violently rubbing of Steel will presently make it so hot as to be able to burn ones fingers Next that the whole force of the stroke is exerted upon that small part where the Flint and Steel first touch For the Bodies being each of them so very hard the puls cannot be far communicated that is the parts of each can yield but very little and therefore the violence of the concussion will be exerted on that piece of Steel which is cut off by the Flint Thirdly that the filings or small parts of Steel are very apt as it were to take fire and are presently red hot that is there seems to be a very combustible sulphureous Body in Iron or Steel which the Air very readily preys upon as soon as the body is a little violently heated And this is obvious in the filings of Steel or Iron cast through the flame of a Candle for even by that sudden transitus of the small chips of Iron they are heat red hot and that combustible sulphureous Body is presently prey'd upon and devoured by the aereal incompassing Menstruum whose office in this Particular I have shewn in the Explication of Charcole And in prosecution of this Experiment having taken the filings of Iron and Steel and with the point of a Knife cast them through the flame of a Candle I observed where some conspicuous shining Particles fell and looking on them with my Microscope I found them to be nothing else but such round Globules as I formerly found the Sparks struck from the Steel by a stroke to be only a little bigger and shaking together all the filings that had fallen upon the sheet of Paper underneath and observing them with the Microscope I found a great number of small Globules such as the former though there were also many of the parts that had remained untoucht and rough filings or chips of Iron So that it seems Iron does contain a very combustible sulphureous Body which is in all likelihood one of the causes of this Phaenomenon and which may be perhaps very much concerned in the business of its hardening and tempering of which somewhat is said in the Description of Muscovy-glass So that these things considered we need not trouble our selves to find out what kind of Pores they are both in the Flint and Steel that contain the Atoms of fire nor how those Atoms come to be hindred from running all out when a dore or passage in their Pores is made by the concussion nor need we trouble our selves to examine by what Prometheus the Element of Fire comes to be fetcht down from above the Regions of the Air in what Cells or Boxes it is kept and what Epimetheus lets it go Nor to consider what it is that causes so great a conflux of the atomical Particles of Fire which are said to fly to a flaming Body like Vultures or Eagles to a putrifying Carcass and there to make a very great pudder Since we have nothing more difficult in this Hypothesis to conceive first as to the kindling of Tinder then how a large Iron-bullet let fall red or glowing hot upon a heap of Small-coal should set fire to those that are next to it first Nor secondly is this last more difficult to be explicated then that a Body as Silver for Instance put into a weak Menstruum as unrectified Aqua fortis should when it is put in a great heat be there dissolved by it and not before which
the water can very little or not at all penetrate this therefore retaining always very neer the same dimensions and the other stretching and shrinking according as there is more or less moisture or water in its pores by reason of the make and shape of the parts the whole body must necessarily unwreath and wreath it self And upon this Principle it is very easie to make several sorts of contrivances that should thus wreath and unwreath themselves either by heat and cold or by driness and moisture or by any greater or less force from whatever cause it proceed whether from gravity or weight or from wind which is motion of the Air or from some springing body or the like This had I time I should enlarge much more upon for it seems to me to be the very first footstep of Sensation and Animate motion the most plain simple and obvious contrivance that Nature has made use of to produce a motion next to that of Rarefaction and Condensation by heat and cold And were this Principle very well examin'd I am very apt to think it would afford us a very great help to find out the Mechanism of the Muscles which indeed as farr as I have hitherto been able to examine seems to me not so very perplex as one might imagine especially upon the examination which I made of the Muscles of Crabs Lobsters and several sorts of large Shell-fish and comparing my Observations on them with the circumstances I observ'd in the muscles of terrestrial Animals Now as in this Instance of the Beard of a wilde Oat we see there is nothing else requisite to make it wreath and unwreath it self and to streighten and bend its knee then onely a little breath of moist or dry Air or a small atome almost of water or liquor and a little heat to make it again evaporate for by holding this Beard plac'd and fix'd as I before directed neer a Fire and dipping the tip of a small shred of Paper in well rectify'd spirit of Wine and then touching the wreath'd Cylindrical part you may perceive it to untwist it self and presently again upon the avolation of the spirit by the great heat it will re-twist it self and thus will it move forward and backwards as oft as you repeat the touching it with the spirit of Wine so may perhaps the shrinking and relaxing of the muscles be by the influx and evaporation of some kind of liquor or juice But of this Enquiry I shall add more elsewhere Observ. XXVIII Of the Seeds of Venus looking-glass or Corn Violet FRom the Leaves and Downs and Beards of Plants we come at last to the Seeds and here indeed seems to be the Cabinet of Nature wherein are laid up its Jewels The providence of Nature about Vegetables is in no part manifested more then in the various contrivances about the seed nor indeed is there in any part of the Vegetable so curious carvings and beautifull adornments as about the seed this in the larger sorts of seeds is most evident to the eye nor is it less manifest through the Microscope in those seeds whose shape and structure by reason of their smalness the eye is hardly able to distinguish Of these there are multitudes many of which I have observ'd through a Microscope and find that they do for the most part every one afford exceeding pleasant and beautifull objects For besides those that have various kinds of carv'd surfaces there are other that have smooth and perfectly polish'd surfaces others a downy hairy surface some are cover'd onely with a skin others with a kind of shell others with both as is observable also in greater seeds Schem XVII Schem XVIII This though it appear'd one of the most promising seeds for beauty to the naked eye yet through the Microscope it appear'd but a rude mishapen seed which I therefore drew that I might thereby manifest how unable we are by the naked eye to judge of beauteous or less curious microscopical Objects cutting some of them in sunder I observ'd them to be fill'd with a greenish yellow pulp and to have a very thick husk in proportion to the pulp Observ. XXIX Of the seeds of Tyme THese pretty fruits here represented in the 18. Scheme are nothing else but nine several seeds of Tyme they are all of them in differing posture both as to the eye and the light nor are they all of them exactly of the same shape there being a great variety both in the bulk and figure of each seed but they all agreed in this that being look'd on with a Microscope they each of them exactly resembled a Lemmon or Orange dry'd and this both in shape and colour Some of them are a little rounder of the shape of an Orange as A and B they have each of them a very conspicuous part by which they were join'd to their little stalk and one of them had a little piece of stalk remaining on the opposite side of the seed you may perceive very plainly by the Figure is very copped and prominent as is very usual in Lemmons which prominencies are express'd in D E and F. They seem'd each of them a little creas'd or wrinckled but E was very conspicuously furrow'd as if the inward make of this seed had been somewhat like that of a Lemmon also but upon dividing several seeds with a very sharp Pen-knife and examining them afterward I found their make to be in nothing but bulk differing from that of Peas that is to have a pretty thick coat and all the rest an indifferent white pulp which seem'd very close so that it seems Nature does not very much alter her method in the manner of inclosing and preserving the vital Principle in the seed in these very small grains from that of Beans Peas c. The Grain affords a very pretty Object for the Microscope namely a Dish of Lemmons plac'd in a very little room should a Lemmon or Nut be proportionably magnify'd to what this seed of Tyme is it would make it appear as bigg as a large Hay-teek and it would be no great wonder to see Homers Iliads and Homer and all cramm'd into such a Nut-shell We may perceive even in these small Grains as well as in greater how curious and carefull Nature is in preserving the seminal principle of Vegetable bodies in what delicate strong and most convenient Cabinets she lays them and closes them in a pulp for their safer protection from outward dangers and for the supply of convenient alimental juice when the heat of the Sun begins to animate and move these little automanâ—â—s or Engines as if she would from the ornaments wherewith she as deckt these Cabinets hint to us that in them she has laid up her Jewels and Master-pieces And this if we are but diligent in observing we shall find her method throughout There is no curiosity in the Elemental kingdom if I may so call the bodies of Air Water Earth that are comparable in
fluid to it we are to consider also the congruity of the parts of the contein'd fluid one with another And this Congruity that I may here a little further explain it is both a Tenaceous and an Attractive power for the Congruity in the Vibrative motions may be the cause of all kind of attraction not only Electrical but Magnetical also and therefore it may be also of Tenacity and Glutinousness For from a perfect congruity of the motions of two distant bodies the intermediate fluid particles are separated and droven away from between them and thereby those congruous bodies are by the incompassing mediums compell'd and forced neerer together wherefore that attractiveness must needs be stronger when by an immediate contact they are forc'd to be exactly the same As I shew more at large in my Theory of the Magnet And this hints to me the reason of the suspension of the Mercury many inches nay many feet above the usual station of 30 inches For the parts of Quick-silver being so very similar and congruous to each other if once united will not easily suffer a divulsion And the parts of water that were any wayes heterogeneous being by exantlation or rarefaction exhausted the remaining parts being also very similar will not easily part neither And the parts of the Glass being solid are more difficulty disjoyn'd and the water being somewhat similar to both is as it were a medium to unite both the Glass and the Mercury together So that all three being united and not very dissimilar by means of this contact if care be taken that the Tube in erecting be not shogged the Quicksilver will remain suspended notwithstanding its contrary indeavour of Gravity a great height above its ordinary Station but if this immediate Contact be removed either by a meer separation of them one from another by the force of a shog whereby the other becomes imbodied between them and licks up from the surface some agil parts and so hurling them makes them air or else by some small heterogeneous agil part of the Water or Air or Quicksilver which appears like a bubble and by its jumbling to and fro there is made way for the heterogeneous Aether to obtrude it self between the Glass and either of the other Fluids the Gravity of Mercury precipitates it downward with very great violence and if the Vessel that holds the restagnating Mercury be convenient the Mercury will for a time vibrate to and fro with very large reciprocations and at last will remain kept up by the pressure of the external Air at the height of neer thirty inches And whereas it may be objected that it cannot be that the meer imbodying of the Aether between these bodies can be the cause since the Aether having a free passage alwayes both through the Pores of the Glass and through those of the Fluids there is no reason why it should not make a separation at all times whilst it remains suspended as when it is violently dis-joyned by a shog To this I answer That though the Aether passes between the Particles that is through the Pores of bodies so as that any chasme or separation being made it has infinite passages to admit its entry into it yet such is the tenacity or attractive virtue of Congruity that till it be overcome by the meer strength of Gravity or by a shog assisting that Conatus of Gravity or by an agil Particle that is like a leaver agitated by the Aether and thereby the parts of the congruous substances are separated so far asunder that the strength of congruity is so far weakened as not to be able to reunite them the parts to be taken hold of being removed out of the attractive Sphere as I may so speak of the congruity such I say is the tenacity of congruity that it retains and holds the almost contiguous Particles of the Fluid and suffers them not to be separated till by meer force that attractive or retentive faculty be overcome But the separation being once made beyond the Sphere of the attractive activity of congruity that virtue becomes of no effect at all but the Mercury freely falls downwards till it meet with a resistance from the pressure of the ambient Air able to resist its gravity and keep it forced up in the Pipe to the height of about thirty inches Thus have I gently raised a Steel pendulum by a Loadstone to a great Angle till by the shaking of my hand I have chanced to make a separation between them which is no sooner made but as if the Loadstone had retained no attractive virtue the Pendulum moves freely from it towards the other side So vast a difference is there between the attractive virtue of the Magnet when it acts upon a contiguous and upon a disjoyned body and much more must there be between the attractive virtues of congruity upon a contiguous and disjoyned body and in truth the attractive virtue is so little upon a body disjoyned that though I have with a Microscope observed very diligently whether there were any extraordinary protuberance on the side of a drop of water that was exceeding neer to the end of a green stick but did not touch it I could not perceive the least though I found that as soon as ever it toucht it the whole drop would presently unite it self with it so that it seems an absolute contact is requisite to the exercising of the tenacious faculty of congruity Observ. VII Of some Phaenomena of Glass drops THese Glass Drops are small â—parcels of coarse green Glass taken out of the Pots that contain the Metal as they call it in fusion upon the end of an Iron Pipe and being exceeding hot and thereby of a kind of sluggish fluid Consistence are suffered to drop from thence into a Bucket of cold Water and in it to lye till they be grown sensibly cold Some of these I broke in the open air by snapping off a little of the small stem with my fingers others by crushing it with a small pair of Plyers which I had no sooner done then the whole bulk of the drop flew violently with a very brisk noise into multitudes of small pieces some of which were as small as dust though in some there were remaining pieces pretty large without any flaw at all and others very much flaw'd which by rubbing between ones fingers was easily reduced to dust these dispersed every way so violently that some of them pierced my skin I could not find either with my naked Eye or a Microscope that any of the broken pieces were of a regular figure nor any one like another but for the most part those that flaw'd off in large pieces were prettily branched The ends of others of these drops I nipt off whilst all the bodies and ends of them lay buried under the water which like the former flew all to pieces with as brisk a noise and as strong a motion Others of these I tried to break by
distant from D towards F and the Ray AFC the production of KCAI will exhibit a Red because the side AF is adjacent to the dark or quiet medium of the eye APFA but nothing of a Blue because its side CF is adjacent to the enlightned medium CFDC and all the Rays from the intermediate parts of the luminous body that are collected between F and D shall have their Red so much the more diluted by how much the farther they are distant from F towards D. Now because by the refraction in the Cornea and some other parts of the eye the sides of each Ray which before were almost parallel are made to converge and meet in a point at the bottom of the eye therefore that side of the pulse which preceded before these refractions shall first touch the Retina and the other side last And therefore according as this or that side or end of the pulse shall be impeded accordingly will the impressions on the Retina be varied therefore by the Ray GACH refracted by the Cornea to D there shall be on that point a stroke or impression confus'd whose weakest end namely that by the line CD shall precede and the stronger namely that by the line AD shall follow And by the Ray KCAI refracted to F there shall be on that part a confus'd stroke or impression whose strongest part namely that by the line CF shal precede and whose weakest or impeded namely that by the line AF shall follow and all the intermediate points between F and D will receive impression from the converg'd Rays so much the more like the impressions on F and D by how much the nearer they approach that or this From the consideration of the proprieties of which impressions we may collect these short definitions of Colours That Blue is an impression on the Retina of an oblique and confus'd pulse of light whose weakest part precedes and whose strongest follows And that Red is an impression on the Retina of an oblique and confus'd pulse of light whose strongest part precedes and whose weakest follows Which proprieties as they have been already manifested in the Prisme and falling drops of Rain to be the causes of the colours there generated may be easily found to be the efficients also of the colours appearing in thin laminated transparent bodies for the explication of which all this has been premised And that this is so a little closer examination of the Phaenomena and the Figure of the body by this Hypothesis will make evident For first as we have already observed the laminated body must be of a determinate thickness that is it must not be thinner then such a determinate quantity for I have always observ'd that neer the edges of those which are exceeding thin the colours disappear and the part grows white nor must it be thicker then another determinate quantity for I have likewise observ'd that beyond such a thickness no colours appear'd but the Plate looked white between which two determinate thicknesses were all the colour'd Rings of which in some substances I have found ten or twelve in others not half so many which I suppose depends much upon the transparency of the laminated body Thus though the consecutions are the same in the scumm or the skin on the top of metals yet in those consecutions the same colour is not so often repeated as in the consecutions in thin Glass or in Sope-water or any other more transparent and glutinous liquor for in these I have observ'd Red Yellow Green Blue Purple Red Yellow Green Blue Purple Red Yellow Green Blue Purple Red Yellow c. to succeed each other ten or twelve times but in the other more opacous bodies the consecutions will not be half so many And therefore secondly the laminated body must be transparent and this I argue from this that I have not been able to produce any colour at all with an opacous body though never so thin And this I have often try'd by pressing a small Globule of Mercury between two smooth Plates of Glass whereby I have reduc'd that body to a much greater thinness then was requisite to exhibit the colours with a transparent body Thirdly there must be a considerable reflecting body adjacent to the under or further side of the lamina or plate for this I always found that the greater that reflection was the more vivid were the appearing colours From which Observations it is most evident that the reflection from the under or further side of the body is the principal cause of the production of these colours which that it is so and how it conduces to that effect I shall further explain in the following Figure which is here described of a very great thickness as if it had been view'd through the Microscope and 't is indeed much thicker than any Microscope I have yet us'd has been able to shew me those colour'd plates of Glass or Muscovie-glass which I have not without much trouble view'd with it for though I have endeavoured to magnifie them as much as the Glasses were capable of yet are they so exceeding thin that I have not hitherto been able positively to determine their thickness This Figure therefore I here represent is wholy Hypothetical Let ABCDHFE in the sixth Figure be a frustum of Muscovy-glass thinner toward the end AE and thicker towards DF. Let us first suppose the Ray aghb coming from the Sun or some remote luminous object to fall obliquely on the thinner plate BAE part therefore is reflected back by cghd the first Superficies whereby the perpendicular pulse ab is after reflection propagated by cd cd equally remote from each other with ab ab so that ag + gc or bh + hd are either of them equal to aa as is also cc but the body BAE being transparent a part of the light of this Ray is refracted in the surface AB and propagated by gikh to the surface EF whence it is reflected and refracted again by the surface AB So that after two refractions and one reflection there is propagated a kind of fainter Ray emnf whose pulse is not only weaker by reason of the two refractions in the surface AB but by reason of the time spent in passing and repassing between the two surfaces AB and EF ef which is this fainter or weaker pulse comes behind the pulse cd so that hereby the surfaces AB and EF being so neer together that the eye cannot discriminate them from one this confus'd or duplicated pulse whose strongest part precedes and whose weakest follows does produce on the Retina or the optick nerve that covers the bottom of the eye the sensation of a Yellow And secondly this Yellow will appear so much the deeper by how much the further back towards the middle between cd and cd the spurious pulse ef is remov'd as in 2 where the surface BC being further remov'd from EF the weaker pulse ef will be nearer to the middle and will make an
there very much condens'd and consequently presses very strongly to get a passage out without suffering the least bubble to pass through its substance For as to the first since our Microscope informs us that the substance of Cork is altogether fill'd with Air and that that Air is perfectly enclosed in little Boxes or Cells distinct from one another It seems very plain why neither the Water nor any other Air can easily insinuate it self into them since there is already within them an intus existens and consequently why the pieces of Cork become so good floats for Nets and stopples for Viols or other close Vessels And thirdly if we enquire why Cork has such a springiness and swelling nature whem compress'd and how it comes to suffer so great a compression or seeming penetration of dimensions so as to be made a substance as heavie again and more bulk for bulk as it was before compression and yet suffer'd to return is found to extend it self again into the same space Our Microscope will easily inform us that the whole mass consists of an infinite company of small Boxes or Bladders of Air which is a substance of a springy nature and that will suffer a considerable condensation as I have several times found by divers trials by which I have most evidently condens'd it into less then a twentieth part of its usual dimensions neer the Earth and that with no other strength then that of my hands without any kind of forcing Engine such as Racks Leavers Wheels Pullies or the like but this onely by and by and besides it seems very probable that those very films or sides of the pores have in them a springing quality as almost all other kind of Vegetable substances have so as to help to restore themselves to their former position And could we so easily and certainly discover the Schematisme and Texture even of these films and of several other bodies as we can these of Cork there seems no probable reason to the contrary but that we might as readily render the true reason of all their Phaenomena as namely what were the cause of the springiness and toughness of some both as to their flexibility and restitution What of the friability or brittleness of some others and the like but till such time as our Microscope or some other means enable us to discover the true Schematism and Texture of all kinds of bodies we must grope as it were in the dark and onely ghess at the true reasons of things by similitudes and comparisons Schem XI To proceed then Cork seems to be by the transverse constitution of the pores a kind of Fungus or Mushrome for the pores lie like so many Rays tending from the center or pith of the tree outwards so that if you cut off a piece from a board of Cork transversly to the flat of it you will as it were split the pores and they will appear just as they are express'd in the Figure B of the XI Scheme But if you shave off a very thin piece from this board parallel to the plain of it you will cut all the pores transversly and they will appear almost as they are express'd in the Figure A save onely the solid Interstitia will not appear so thick as they are there represented So that Cork seems to suck its nourishment from the subjacent bark of the Tree immediately and to be a kind excrescence or a substance distinct from the substances of the entire Tree something analogus to the Mushrome or Moss on other Trees or to the hairs on Animals And having enquir'd into the History of Cork I find it reckoned as an excrescency of the bark of a certain Tree which is distinct from the two barks that lie within it which are common also to other trees That 't is some time before the Cork that covers the young and tender sprouts comes to be discernable That it cracks flaws and cleaves into many great chaps the bark underneath remaining entire That it may be separated and remov'd from the Tree and yet the two under-barks such as are also common to that with other Trees not at all injur'd but rather helped and freed from an external injury Thus Ionstonus in Dendrologia speaking de Subere says Arbor est procera Lignum est robustum dempto cortice in aquis non fluitat Cortice in orbem detracto juvatur crascescens enim praestringit strangulat intra triennium iterum repletur Caudex ubi adolescit crassus cortex superior densus carnosus duos digitos crassus scaber rimosus qui nisi detrahatur dehiscit alioque subnascente expellitur interior qui subest novellus ita rubet ut arbor minio picta videatur Which Histories if well consider'd and the tree substance and manner of growing if well examin'd would I am very apt to believe much confirm this my conjecture about the origination of Cork Nor is this kind of Texture peculiar to Cork onely for upon examination with my Microscope I have found that the pith of an Elder or almost any other Tree the inner pulp or pith of the Cany hollow stalks of several other Vegetables as of Fennel Carrets Daucus Bur-docks Teasels Fearn some kinds of Reeds c. have much such a kind of Schematisme as I have lately shewn that of Cork save onely that here the pores are rang'd the long-ways or the same ways with the length of the Cane whereas in Cork they are transverse The pith also that fills that part of the stalk of a Feather that is above the Quil has much such a kind of texture save onely that which way soever I set this light substance the pores seem'd to be cut transversly so that I ghess this pith which fills the Feather not to consist of abundance of long pores separated with Diaphragms as Cork does but to be a kind of solid or hardned froth or a congeries of very small bubbles consolidated in that form into a pretty stiff as well as tough concrete and that each Cavern Bubble or Cell is distinctly separate from any of the rest without any kind of hole in the encompassing films so that I could no more blow through a piece of this kinde of substance then I could through a piece of Cork or the sound pith of an Elder But though I could not with my Microscope nor with my breath nor any other way I have yet try'd discover a passage out of one of those cavities into another yet I cannot thence conclude that therefore there are none such by which the Succus nutritius or appropriate juices of Vegetables may pass through them for in several of those Vegetables whil'st green I have with my Microscope plainly enough discover'd these Cells or Poles fill'd with juices and by degrees sweating them out as I have also observed in green Wood all those long Microscopical pores which appear in Charcoal perfectly empty of any thing but Air. Now though I have with great
the Glass for though perhaps it does make the several specks more radiant and glaring yet by that means uniting more Rays very near to one point it does make many of those radiant points conspicuous which by putting on a less aperture may be found to vanish and therefore both for the discovery of the fixt Star and for finding the Satellites of Iupiter before it be out of the day or twilight I alwayes leave the Object-glass as clear without any aperture as I can and have thereby been able to discover the Satellites a long while before I was able to discern them when the smaller apertures were put on and at other times to see multitudes of other smaller Stars which a smaller aperture makes to disappear In that notable Asterism also of the Sword of Orion where the ingenious Monsieur Hugens van Zulichem has discovered only three little Stars in a cluster I have with a thirty six foot Glass without any aperture the breadth of the Glass being about some three inches and a half discover'd five and the twinkling of divers others up and down in divers parts of that small milky Cloud So that 't is not unlikely but that the meliorating of Telescopes will afford as great a variety of new Discoveries in the Heavens as better Microscopes would among small terrestrial Bodies and both would give us infinite cause more and more to admire the omnipotence of the Creator Observ. LX. Of the Moon Schem XXXVIII Up and down in several parts of this place here describ'd as there are multitudes in other places all over the surface of the Moon may be perceived several kinds of pits which are shap'd almost like a dish some bigger some less some shallower some deeper that is they sâ—em to be a hollow Hemisphere incompassed with a round rising bank as if the substance in the middle had been digg'd up and thrown on either side These seem to me to have been the effects of some motions within the body of the Moon analogus to our Earthquakes by the eruption of which as it has thrown up a brim or ridge round about higher then the Ambient surface of the Moon so has it left a hole or depression in the middle proportionably lower divers places resembling some of these I have observ'd here in England on the tops of some Hills which might have been caus'd by some Earthquake in the younger dayes of the world But that which does most incline me to this belief is first the generality and diversity of the Magnitude of these pits all over the body of the Moon Next the two experimental wayes by which I have made a representation of them The first was with a very soft and well temper'd mixture of Tobacco-pipe clay and Water into which if I let fall any heavy body as a Bullet it would throw up the mixture round the place which for a while would make a representation not unlike these of the Moon but considering the state and condition of the Moon there seems not any probability to imagine that it should proceed from any cause analogus to this for it would be difficult to imagine whence those bodies should come and next how the substance of the Moon should be so soft but if a Bubble be blown under the surface of it and suffer'd to rise and break or if a Bullet or other body sunk in it be pull'd out from it these departing bodies leave an impression on the surface of the mixture exactly like these of the Moon save that these also quickly subside and vanish But the second and most notable representation was what I observ'd in a pot of boyling Alabaster for there that powder being by the eruption of vapours reduc'd to a kind of fluid consistence if whil'st it boyls it be gently remov'd besides the fire the Alabaster presently ceasing to boyl the whole surface especially that where some of the last Bubbles have risen will appear all over covered with small pits exactly shap'd like these of the Moon and by holding a lighted Candle in a large dark Room in divers positions to this surface you may exactly represent all the Phaenomena of these pits in the Moon according as they are more or less inlightned by the Sun And that there may have been in the Moon some such motion as this which may have made these pits will seem the more probable if we suppose it like our Earth for the Earthquakes here with us seem to proceed from some such cause as the boyling of the pot of Alabaster there seeming to be generated in the Earth from some subterraneous fires or heat great quantities of vapours that is of expanded aerial substances which not presently finding a passage through the ambient parts of the Earth do as they are increased by the supplying and generating principles and thereby having not sufficient room to expand themselves extreamly condens'd at last overpower with their elastick properties the resistence of the incompassing Earth and lifting it up or cleaving it and so shattering of the parts of the Earth above it do at length where they find the parts of the Earth above them more loose make their way upwards and carrying a great part of the Earth before them not only raise a small brim round about the place out of which they break but for the most part considerable high Hills and Mountains and when they break from under the Sea divers times mountainous Islands this seems confirm'd by the Vulcans in several places of the Earth the mouths of which for the most part are incompassed with a Hill of a considerable height and the tops of those Hills or Mountains are usually shap'd very much like these pits or dishes of the Moon Instances of this we have in the descriptions of Aetna in Sicily of Hecla in Iceland of Tenerif in the Canaries of the several Vulcans in New-Spain describ'd by Gage and more especially in the eruption of late years in one of the Canary Islands In all of which there is not only a considerable high Hill raised about the mouth of the Vulcan but like the spots of the Moon the top of those Hills are like a dish or bason And indeed if one attentively consider the nature of the thing one may find sufficient reason to judge that it cannot be otherwise for these eruptions whether of fire or smoak alwayes raysing great quantities of Earth before them must necessarily by the fall of those parts on either side raise very considerable heaps Now both from the figures of them and from several other circumstances these pits in the Moon seem to have been generated much after the same manner that the holes in Alabaster and the Vulcans of the Earth are made For first it is not improbable but that the substance of the Moon may be very much like that of our Earth that is may consist of an earthy sandy or rocky substance in several of its superficial parts which parts being
called by the Names of Driness and Moisture though these two names are not comprehensive enough being commonly used to signifie only the adhering or not adhering of water to some other solid Bodies of this kind we may observe that water will more readily wet some woods then others and that water let fall upon a Feather the whiter side of a Colworâ— and some other leaves or upon almost any dusty unctuous or resinous superficies will not at all adhere to them but easily tumble off from them like a solid Bowl whereas if dropt upon Linnen Paper Clay green Wood c. it will not be taken off without leaving some part of it behind adhering to them So Quick-silver which will very hardly be brought to stick to any vegetable body will readily adhere to and mingle with several clean metalline bodies And that we may the better finde what the cause of Congruity and Incongruity in bodies is it will be requisite to consider First what is the cause of fluidness And this I conceive to be nothing else but a certain pulse or shake of heat for Heat being nothing else but a very brisk and vehement agitation of the parts of a body as I have elsewhere made probabable the parts of a body are thereby made so loose from one another that they easily move any way and become fluid That I may explain this a little by a gross Similitude let us suppose a dish of sand set upon some body that is very much agitated and shaken with some quick and strong vibrating motion as on a Milstone turn'd round upon the under stone very violently whilst it is empty or on a very stiff Drum-head which is vehemently or very nimbly beaten with the Drumsticks By this means the sand in the dish which before lay like a dull and unactive body becomes a perfect fluid and ye can no sooner make a hole in it with your finger but it is immediately filled up again and the upper surface of it levell'd Nor can you bury a light body as a piece of Cork under it but it presently emerges or swims as 't were on the top nor can you lay a heavier on the top of it as a piece of Lead but it is immediately buried in Sand and as 't were sinks to the bottom Nor can you make a hole in the side of the Dish but the sand shall run out of it to a level not an obvious property of a fluid body as such but this dos imitate and all this meerly caused by the vehement agitation of the conteining vessel for by this means each sand becomes to have a vibrative or dancing motion so as no other heavier body can rest on it unless sustain'd by some other on either side Nor will it suffer any Body to be beneath it unless it be a heavier then it self Another Instance of the strange loosening nature of a violent jarring Motion or a strong and nimble vibrative one we may have from a piece of iron grated on very strongly with a file for if into that a pin be screw'd so firm and hard that though it has a convenient head to it yet it can by no means be unscrew'd by the fingers if I say you attempt to unscrew this whilst grated on by the file it will be found to undoe and turn very easily The first of these Examples manifests how a body actually divided into small parts becomes a fluid And the latter manifest by what means the agitation of heat so easily loosens and unties the parts of solid and firm bodies Nor need we suppose heat to be any thing else besides such a motion for supposing we could Mechanically produce such a one quick and strong enough we need not spend fuel to melt a body Now that I do not speak this altogether groundless I must refer the Reader to the Observations I have made upon the shining sparks of Steel for there he shall find that the same effects are produced upon small chips or parcels of Steel by the flame and by a quick and violent motion and if the body of steel may be thus melted as I there shew it may I think we have little reason to doubt that almost any other may not also Every Smith can inform one how quickly both his File and the Iron grows hot with filing and if you rub almost any two hard bodies together they will do the same And we know that a sufficient degree of heat causes fluidity in some bodies much sooner and in others later that is the parts of the body of some are so loose from one another and so unapt to cohere and so minute and little that a very small degree of agitation keeps them always in the state of fluidity Of this kind I suppose the Aether that is the medium or fluid body in which all other bodies do as it were swim and move and particularly the Air which seems nothing else but a kind of tincture or solution of terrestrial and aqueous particles dissolv'd into it and agitated by it just as the tincture of Cocheneel is nothing but some finer dissoluble parts of that Concrete lick'd up or dissolv'd by the fluid water And from this Notion of it we may easily give a more Intelligible reason how the Air becomes so capable of Rarefaction and Condensation For as in tinctures one grain of some strongly tinging substance may sensibly colour some hundred thousand grains of appropriated Liquors so as every drop of it has its proportionate share and be sensibly ting'd as I have try'd both with Logwood and Cocheneel And as some few grains of Salt is able to infect as great a quantity as may be found by praecipitations though not so easily by the sight or aste so the Air which seems to be but as 't were a tincture or saline substance dissolv'd and agitated by the fluid and agil Aether may disperse and expand it self into a vast space if it have room enough and infect as it were every part of that space But as on the other side if there be but some few grains of the liquor it may extract all the colour of the tinging substance and may dissolve all the Salt and thereby become much more impregnated with those substances so may all the air that sufficed in a rarify'd state to fill some hundred thousand spaces of Aether be compris'd in only one but in a position proportionable dense And though we have not yet found out such strainers for Tinctures and Salts as we have for the Air being yet unable to separate them from their dissolving liquors by any kind of filtre without praecipitation as we are able to separate the Air from the Aether by Glass and several other bodies And though we are yet unable and ignorant of the ways of praecipitating Air out of the Aether as we can Tinctures and Salts out of several dissolvents yet neither of these seeming impossible from the nature of the things nor so improbable
but that some happy future industry may find out ways to effect them nay further since we find that Nature does really perform though by what means we are not certain both these actions namely by praecipitating the Air in Rain and Dews and by supplying the Streams and Rivers of the World with fresh water strain'd through secret subterraneous Caverns And since that in very many other proprieties they do so exactly seem of the same nature till further observations or tryals do inform us of the contrary we may safely enough conclude them of the same kind For it seldom happens that any two natures have so many properties coincident or the same as I have observ'd Solutions and Air to have and to be different in the rest And therefore I think it neither impossible irrational nay nor difficult to be able to predict what is likely to happen in other particulars also besides those which Observation or Experiment have declared thus or thus especially if the circumstances that do often very much conduce to the variation of the effects be duly weigh'd and consider'd And indeed were there not a probability of this our inquiries would be endless our tryals vain and our greatest inventions would be nothing but the meer products of chance and not of Reason and like Mariners in an Ocean destitute both of a Compass and the sight of the Celestial guids we might indeed by chance Steer directly towards our desired Port but 't is a thousand to one but we miss our aim But to proceed we may hence also give a plain reason how the Air comes to be darkned by clouds c. which are nothing but a kind of precipitation and how those precipitations fall down in Showrs Hence also could I very easily and I think truly deduce the cause of the curious six angular figures of Snow and the appearances of Haloes c. and the sudden thickning of the Sky with Clouds and the vanishing and disappearing of those Clouds again for all these things may be very easily imitated in a glass of liquor with some slight Chymical preparations as I have often try'd and may somewhere else more largely relate but have not now time to set them down But to proceed there are other bodies that consist of particles more Gross and of a more apt figure for cohesion and this requires a somewhat greater agitation such I suppose ☿ fermented vinous Spirits several Chymical Oils which are much of a kin to those Spirits c. Others yet require a greater as water and so others much greater for almost infinite degrees For I suppose there are very few bodies in the world that may not be made aliquatenus fluid by some or other degree of agitation or heat Having therefore in short set down my Notion of a Fluid body I come in the next place to consider what Congruity is and this as I said before being a Relative property of a fluid whereby it may be said to be like or unlike to this or that other body whereby it does or does not mix with this or that body We will again have recourse to our former Experiment though but a rude one and here if we mix in the dish several kinds of sands some of bigger others of less and finer bulks we shall find that by the agitation the fine sand will eject and throw out of it self all those bigger bulks of small stones and the like and those will be gathered together all into one place and if there be other bodies in it of other natures those also will be separated into a place by themselves and united or tumbled up together And though this do not come up to the highest property of Congruity which is a Cohaesion of the parts of the fluid together or a kind of attraction and tenacity yet this does as 't were shadow it out and somewhat resemble it for just after the same manner I suppose the pulse of heat to agitate the small parcels of matter and those that are of a like bigness and figure and matter will hold or dance together and those which are of a differing kind will be thrust or shov'd out from between them for particles that are all similar will like so many equal musical strings equally strecht vibrate together in a kind of Harmony or unison whereas others that are dissimilar upon what account soever unless the disproportion be otherwise counter-ballanc'd will like so many strings out of tunne to those unisons though they have the same agitating pulse yet make quite differing kinds of vibrations and repercussions so that though they may be both mov'd yet are their vibrations so different and so untun'd as 't were to each other that they cross and jar against each other and consequently cannot agree together but fly back from each other to their similar particles Now to give you an instance how the disproportion of some bodies in one respect may be counter-ballanc'd by a contrary disproportion of the same body in another respect whence we find that the subtil vinous spirit is congruous or does readily mix with water which in many properties is of a very differing nature we may consider that a unison may be made either by two strings of the same bigness length and tension or by two strings of the same bigness but of differing length and a contrary differing tension or 3 ly by two strings of unequal length and bigness and of a differing tension or of equal length and differing bigness and tension and several other such varieties To which three properties in strings will correspond three proprieties also in sand or the particles of bodies their Matter or Substance their Figure or Shape and their Body or Bulk And from the varieties of these three may arise infinite varieties in fluid bodies though all agitated by the same pulse or vibrative motion And there may be as many ways of making Harmonies and Discords with these as there may be with musical strings Having therefore seen what is the cause of Congruity or Incongruity those relative properties of fluids we may from what has been said very easily collect what is the reason of those Relative proprieties also between fluid bodies and solid for since all bodies consist of particles of such a Substance Figure and Bulk but in some they are united together more firmly then to be loosened from each other by every vibrative motion though I imagine that there is no body in the world but that some degree of agitation may as I hinted before agitate and loosen the particles so as to make them fluid those cohering particles may vibrate in the same manner almost as those that are loose and become unisons or discords as I may so speak to them Now that the parts of all bodies though never so solid do yet vibrate I think we need go no further for proof then that all bodies have some degrees of heat in them and that there has not
ebbing and flowing resembleth the unstable motions of the Sea The Phaenomena of which two may be easily made out by supposing the Cavern by which they are fed to arise from the bottom of the next Sea A Third is a Well upon the River Ogmore in Glamorganshire and near unto Newton of which Camden relates himself to be certified by a Letter from a Learned Friend of his that observed it Fons abest hinc c. The Letter is a little too long to be inserted but the substance is this That this Well ebbs and flows quite contrary to the flowing and ebbing of the Sea in those parts for 't is almost empty at Full Sea but full at Low water This may happen from the Channel by which it is supplied which may come from the bottom of a Sea very remote from those parts and where the Tides are much differing from those of the approximate shores A Fourth lies in Westmorland near the River Loder Qui instar Euripi saepius in die reciprocantibus undis fluit refluit which ebbs and flows many times a day This may proceed from its being supplyed from many Channels coming from several parts of the Sea lying sufficiently distant asunder to have the times of High-water differing enough one from the other so as that whensoever it shall be High water over any of those places where these Channels begin it shall likewise be so in the Well but this is but a supposition A Seventh Query was Whether the dissolution or mixing of several bodies whether fluid or solid with saline or other Liquors might not partly be attributed to this Principle of the congruity of those bodies and their dissolvents As of Salt in Water Metals in several Menstruums Unctuous Gums in Oyls the mixing of Wine and Water c. And whether precipitation be not partly made from the same Principle of Incongruity I say partly because there are in some Dissolutions some other Causes concurrent I shall lastly make a much more seemingly strange and unlikely Query and that is Whether this Principle well examined and explained may not be found a co-efficient in the most considerable Operations of Nature As in those of Heat and Light and consequently of Rarefaction and Condensation Hardness and Fluidness Perspicuity and Opacousness Refractions and Colours c. Nay I know not whether there may be many things done in Nature in which this may not be said to have a Finger This I have in some other passages of this Treatise further enquired into and shewn that as well Light as Heat may be caused by corrosion which is applicable to congruity and consequently all the rest will be but subsequents In the mean time I would not willingly be guilty of that Error which the thrice Noble and Learned Verulam justly takes notice of as such and calls Philosophiae Genus Empiricum quod in paucorum Experimentorum Angustiis Obscuritate fundatum est For I neither conclude from one single Experiment nor are the Experiments I make use of all made upon one Subject Nor wrest I any Experiment to make it quadrare with any preconceiv'd Notion But on the contrary 〈◊〉 endeavour to be conversant in divers kinds of Experiments and all 〈◊〉 every one of those Trials I make the Standards or Touchstones by which I try all my former Notions whether they hold out in weight and measure and touch c. For as that Body is no other then a Counterfeit Gold which wants any one of the Proprieties of Gold such as are the Malleableness Weight Colour Fixtness in the Fire Indissolubleness in Aqua fortis and the like though it has all the other so will all those Notions be found to be false and deceitful that will not undergo all the Trials and Tests made of them by Experiments And therefore such as will not come up to the desired Apex of Perfection I rather wholly reject and take new then by piecing and patching endeavour to retain the old as knowing such things at best to be but lame and imperfect And this course I learned from Nature whom we find neglectful of the old Body and suffering its Decaies and Infirmities to remain without repair and altogether sollicitous and careful of perpetuating the Species by new Individuals And it is certainly the most likely way to erect a glorious Structure and Temple to Nature such as she will be found by any zealous Votary to refide in to begin to build a new upon a sure Foundation of Experiments But to digress no further from the consideration of the Phaenomena more immediately explicable by this Experiment we shall proceed to shew That as to the rising of Water in a Filtre the reason of it will be manifest to him that does take notice that a Filtre is constituted of a great number of small long solid bodies which lie so close together that the Air in its getting in between them doth lose of its pressure that it has against the Fluid without them by which means the Water or Liquor not finding so strong a resistance between them as is able to counter-ballance the pressure on its superficies without is raised upward till it meet with a pressure of the Air which is able to hinder it And as to the Rising of Oyl melted Tallow Spirit of Wine c. in the Week of a Candle or Lamp it is evident that it differs in nothing from the former save only in this that in a Filtre the Liquor descends and runs away by another part and in the Week the Liquor is dispersed and carried away by the Flame something there is ascribable to the Heat for that it may ratifie the more volatil and spirituous parts of those combustible Liquors and so being made lighter then the Air it may be protruded upwards by that more ponderous fluid body in the Form of Vapours but this can be ascribed to the ascension of but a very little and most likely of that only which ascends without the Week As for the Rising of it in a Spunge Bread Cotton c. above the superficies of the subjacent Liquor what has been said about the Filtre if considered will easily suggest a reason considering that all these bodies abound with small holes or pores From this same Principle also viz. the unequal pressure of the Air against the unequal superficies of the water proceeds the cause of the accession or incursion of any floating body against the sides of the containing Vessel or the appropinquation of two floating bodies as Bubbles Corks Sticks Straws c. one towards another As for instance Take a Glass-jar such as AB in the seventh Figure and filling it pretty near the top with water throw into it a small round piece of Cork as C and plunge it all over in water that it be wet so as that the water may rise up by the sides of it then placing it any where upon the superficies about an inch or one inch and a
this order it alwayes kept whatsoever were the middle Colour There was further observable in several other parts of this Body many Lines or Threads each of them of some one peculiar Colour and those so exceedingly bright and vivid that it afforded a very pleasant object through the Microscope Some of these threads I have observed also to be pieced or made up of several short lengths of differently coloured ends as I may so call them as a line appearing about two inches long through the Microscope has been compounded of about half an inch of a Peach colour ⅛ of a lovely Grass-green ¾ of an inch more of a bright Scarlet and the rest of the line of a Watchet blew Others of them were much otherwise coloured the variety being almost infinite Another thing which is very observable is that if you find any place where the colours are very broad and conspicuous to the naked eye you may by pressing that place with your finger make the colours change places and go from one part to another There is one Phaenomenon more which may if care be used exhibit to the beholder as it has divers times to me an exceeding pleasant and not less instructive Spectacle And that is if curiosity and diligence be used you may so split this admirable Substance that you may have pretty large Plates in comparison of those smaller ones which you may observe in the Rings that are perhaps an ⅛ or a ⅙ part of an inch over each of them appearing through the Microscope most curiously intirely and uniformly adorned with some one vivid colour this if examined with the Microscope may be plainly perceived to be in all parts of it equally thick Two three or more of these lying one upon another exhibit oftentimes curious compounded colours which produce such a Compositum as one would scarce imagine should be the result of such ingredients As perhaps a faint yellow and a blew may produce a very deep purple But when anon we come to the more strict examination of these Phaenomena and to inquire into the causes and reasons of these productions we shall I hope make it more conceivable how they are produced and shew them to be no other then the natural and necessary effects arising from the peculiar union of concurrent causes These Phaenomena being so various and so truly admirable it will certainly be very well worth our inquiry to examine the causes and reasons of them and to consider whether from these causes demonstratively evidenced may not be deduced the true causes of the production of all kind of Colours And I the rather now do it instead of an Appendix or Digression to this History then upon the occasion of examining the Colours in Peacocks or other Feathers because this Subject as it does afford more variety of particular Colours so does it afford much better wayes of examining each circumstance And this will be made manifest to him that considers first that this laminated body is more simple and regular then the parts of Peacocks feathers this consisting only of an indefinite number of plain and smooth Plates heaped up or incumbent on each other Next that the parts of this body are much more manageable to be divided or joyned then the parts of a Peacocks feather or any other substance that I know And thirdly because that in this we are able from a colourless body to produce several coloured bodies affording all the variety of Colours imaginable And several others which the subsequent Inquiry will make manifest To begin therefore it is manifest from several circumstances that the material cause of the apparition of these several Colours is some Lamina or Plate of a transparent or pellucid body of a thickness very determinate and proportioned according to the greater or less refractive power of the pellucid body And that this is so abundance of Instances and particular Circumstances will make manifest As first if you take any small piece of the Muscovy-glass and with a Needle or some other convenient Instrument cleave it oftentimes into thinner and thinner Laminae you shall find that till you come to a determinate thinness of them they shall all appear transparent and colourless but if you continue to split and divide them further you shall find at last that each Plate after it comes to such a determinate thickness shall appear most lovely ting'd or imbued with a determinate colour If further by any means you so flaw a pretty thick piece that one part does begin to cleave a little from the other and between those two there be by any means gotten some pellucid medium those laminated pellucid bodies that fill that space shall exhibit several Rainbows or coloured Lines the colours of which will be disposed and ranged according to the various thicknesses of the several parts of that Plate That this is so is yet further confirmed by this Experiment Take two small pieces of ground and polisht Looking-glass-plate each about the bigness of a shilling take these two dry and with your fore-fingers and thumbs press them very hard and close together and you shall find that when they approach each other very near there will appear several Irises or coloured Lines in the same manner almost as in the Muscovy-glass and you may very easily change any of the Colours of any part of the interposed body by pressing the Plates closer and harder together or leaving them more lax that is a part which appeared coloured with a red may be presently ting'd with a yellow blew green purple or the like by altering the appropinquation of the terminating Plates Now that air is not necessary to be the interposed body but that any other transparent fluid will do much the same may be tryed by wetting those approximated Surfaces with Water or any other transparent Liquor and proceeding with it in the same manner as you did with the Air and you will find much the like effect only with this difference that those comprest bodies which differ most in their refractive quality from the compressing bodies exhibit the most strong and vivid tinctures Nor is it necessary that this laminated and ting'd body should be of a fluid substance any other substance provided it be thin enough and transparent doing the same thing this the Laminae of our Muscovy-glass hint but it may be confirm'd by multitudes of other Instances And first we shall find that even Glass it self may by the help of a Lamp be blown thin enough to produce these Phaenomena of Colours which Phaenomena accidentally happening as I have been attempting to frame small Glasses with a Lamp did not a little surprize me at first having never heard or seen any thing of it before though afterwards comparing it with the Phaenomena I had often observed in those Bubbles which Children use to make with Soap-water I did the less wonder especially when upon Experiment I found I was able to produce the same Phaenomena in thin
Bubbles made with any other transparent Substance Thus have I produced them with Bubbles of Pitch Rosin Câ—lophony Turpentine Solutions of several Gums as 〈◊〉 Arabick in water any glutinous Liquor as Wort Wine Spirit of Wine Oyl of Turpentine Glare of Snails c. It would be needless to enumerate the several Instances these being enough to shew the generality or universality of this propriety Only I must not omit that we have instances also of this kind even in metalline Bodies and animal for those several Colours which are observed to follow each other upon the polisht surface of hardned Steel when it is by a sufficient degree of heat gradually tempered or softened are produced from nothing else but a certain thin Lamina of a vitrum or vitrified part of the Metal which by that degree of heat and the concurring action of the ambient Air is driven out and fixed on the surface of the Steel And this hints to me a very probable at least if not the true cause of the hardning and tempering of Steel which has not I think been yet given nor that I know of been so much as thought of by any And that is this that the hardness of it arises from a greater proportion of a vitrified Substance interspersed through the pores of the Steel And that the tempering or softning of it arises from the proportionate or smaller parcels of it left within those pores This will seem the more probable if we consider these Particulars First That the pure parts of Metals are of themselves very flexible and tuff that is will indure bending and hammering and yet retain their continuity Next That the Parts of all vitrified Substances as all kinds of Glass the Scoria of Metals c. are very hard and also very brittle being neither flexible nor malleable but may by hammering or beating be broken into small parts or powders Thirdly That all Metals excepting Gold and Silver which do not so much with the bare fire unless assisted by other saline Bodies do more or less vitrifie by the strength of fire that is are corroded by a saline Substance which I elsewhere shew to be the true cause of fire and are thereby as by several other Menstruums converted into Scoria And this is called calcining of them by Chimists Thus Iron and Copper by heating and quenching do turn all of them by degrees into Scoria which are evidently vitrified Substances and unite with Glass and are easily fusible and when cold very hard and very brittle Fourthly That most kind of Vitrifications or Calcinations are made by Salts uniting and incorporating with the metalline Particles Nor do I know any one calcination wherein a Saline body may not with very great probability be said to be an agent or coadjutor Fifthly That Iron is converted into Steel by means of the incorporation of certain salts with which it is kept a certain time in the fire Sixthly That any Iron may in a very little time be case hardned as the Trades-men call it by casing the iron to be hardned with clay and putting between the clay and iron a good quantity of a mixture of Vrine Soot Sea-salt and Horses hoofs all which contein great quantities of Saline bodies and then putting the case into a good strong fire and keeping it in a considerable degree of heat for a good while and afterwards heating and quenching or cooling it suddenly in cold water Seventhly That all kind of vitrify'd substances by being suddenly cool'd become very hard and brittle And thence arises the pretty Phoenomena of the Glass Drops which I have already further explained in its own place Eighthly That those metals which are not so apt to vitrifie do not acquire any hardness by quenching in water as Silver Gold c. These considerations premis'd will I suppose make way for the more easie reception of this following Explication of the Phaenomena of hardned and temper'd Steel That Steel is a substance made out of Iron by means of a certain proportionate Vitrification of several parts which are so curiously and proportionately mixt with the more tough and unalter'd parts of the Iron that when by the great heat of the fire this vitrify'd substance is melted and consequently rarify'd and thereby the pores of the Iron are more open if then by means of dipping it in cold water it be suddenly cold and the parts hardned that is stay'd in that same degree of Expansion they were in when hot the parts become very hard and brittle and that upon the same account almost as small parcels of glass quenched in water grow brittle which we have already explicated If after this the piece of Steel be held in some convenient heat till by degrees certain colours appear upon the surface of the brightned metal the very hard and brittle tone of the metal by degrees relaxes and becomes much more tough and soft namely the action of the heat does by degrees loosen the parts of the Steel that were before streached or set atilt as it were and stayed open by each other whereby they become relaxed and set at liberty whence some of the more brittle interjacent parts are thrust out and melted into a thin skin on the surface of the Steel which from no colour increases to a deep Purple and so onward by these gradations or consecutions White Yellow Orange Minium Scarlet Purple Blew Watchet c. and the parts within are more conveniently and proportionately mixt and so they gradually subside into a texture which is much better proportion'd and closer joyn'd whence that rigidnesse of parts ceases and the parts begin to acquire their former ductilness Now that 't is nothing but the vitrify'd metal that sticks upon the surface of the colour'd body is evident from this that if by any means it be scraped and rubb'd off the metal underneath it is white and clear and if it be kept longer in the fire so as to increase to a considerable thickness it may by blows be beaten off in flakes This is further confirm'd by this observable that that Iron or Steel will keep longer from rusting which is covered with this vitrify'd case Thus also Lead will by degrees be all turn'd into a litharge for that colour which covers the top being scum'd or shov'd aside appears to be nothing else but a litharge or vitrify'd Lead This is observable also in some sort on Brass Copper Silver Gold Tin but is most conspicuous in Lead all those Colours that cover the surface of the Metal being nothing else but a very thin vitrifi'd part of the heated Metal The other Instance we have is in Animal bodies as in Pearls Mother of Pearl-shels Oyster-shels and almost all other kinds of stony shels whatsoever This have I also sometimes with pleasure observ'd even in Muscles and Tendons Further if you take any glutinous substance and run it exceedingly thin upon the surface of a smooth glass or a polisht metaline body you shall
this place Zeictically to examine and positively to prove what particular kind of motion it is that must be the efficient of Light for though it be a motion yet 't is not every motion that produces it since we find there are many bodies very violently mov'd which yet afford not such an effect and there are other bodies which to our other senses seem not mov'd so much which yet shine This Water and quick-silver and most other liquors heated shine not and several hard bodies as Iron Silver Brass Copper Wood c. though very often struck with a hammer shine not presently though they will all of them grow exceeding hot whereas rotten Wood rotten Fish Sea water Gloworms c. have nothing of tangible heat in them and yet where there is no stronger light to affect the Sensory they shine some of them so Vividly that one may make a shift to read by them It would be too long I say here to insert the discursive progress by which I inquir'd after the proprieties of the motion of Light and therefore I shall only add the result And First I found it ought to be exceeding quick such as those motions of fermentation and putrefaction whereby certainly the parts are exceeding nimbly and violently mov'd and that because we find those motions are able more minutely to shatter and divide the body then the most violent heats or menstruums we yet know And that fire is nothing else but such a dissolution of the Burning body made by the most universal menstruum of all sulphureous bodies namely the Air we shall in an other place of this Tractate endeavour to make probable And that in all extreamly hot shining bodies there is a very quick motion that causes Light as well as a more robust that causes Heat may be argued from the celerity wherewith the bodyes are dissolv'd Next it must be a Vibrative motion And for this the newly mention'd Diamond affords us a good argument since if the motion of the parts did not return the Diamond must after many rubbings decay and be wasted but we have no reason to suspect the latter especially if we consider the exceeding difficulty that is found in cutting or wearing away a Diamond And a Circular motion of the parts is much more improbable since if that were granted and they be suppos'd irregular and Angular parts I see not how the parts of the Diamond should hold so firmly together or remain in the same sensible dimensions which yet they do Next if they be Globular and mov'd only with a turbinated motion I know not any cause that can impress that motion upon the pellucid medium which yet is done Thirdly any other irregular motion of the parts one amongst another must necessarily make the body of a fluid consistence from which it is far enough It must therefore be a Vibrating motion And Thirdly That it is a very short vibrating motion I think the instances drawn from the shining of Diamonds will also make probable For a Diamond being the hardest body we yet know in the World and consequently the least apt to yield or bend must consequently also have its vibrations exceeding short And these I think are the three principal proprieties of a motion requisite to produce the effect call'd Light in the Object The next thing we are to consider is the way or manner of the trajection of this motion through the interpos'd pellucid body to the eye And here it will be easily granted First That it must be a body susceptible and impartible of this motion that will deserve the name of a Transparent And next that the parts of such a body must be Homogeneous or of the same kind Thirdly that the constitution and motion of the parts must be such that the appulse of the luminous body may be communicated or propagated through it to the greatest imaginable distance in the least imaginable time though I see no reason to affirm that it must be in an instant For I know not any one Experiment or observation that does prove it And whereas it may be objected That we see the Sun risen at the very instant when it is above the sensible Horizon and that we see a Star hidden by the body of the Moon at the same instant when the Star the Moon and our Eye are all in the same line and the like Observations or rather suppositions may be urg'd I have this to answer That I can as easily deny as they affirm for I would fain know by what means any one can be assured any more of the Affirmative then I of the Negative If indeed the propagation were very slow 't is possible something might be discovered by Eclypses of the Moon but though we should grant the progress of the light from the Earth to the Moon and from the Moon back to the Earth again to be full two Minutes in performing I know not any possible means to discover it nay there may be some instances perhaps of Horizontal Eclypses that may seem very much to favour this supposition of the slower progression of Light then most imagine And the like may be said of the Eclypses of the Sun c. But of this only by the by Fourthly That the motion is propagated every way through an Homogeneous medium by direct or straight lines extended every way like Rays from the center of a Sphere Fifthly in an Homogeneous medium this motion is propagated every way with equal velocity whence necessarily every pulse or vitration of the luminous body will generate a Sphere which will continually increase and grow bigger just after the same manner though indefinitely swifter as the waves or rings on the surface of the water do swell into bigger and bigger circles about a point of it where by the sinking of a Stone the motion was begun whence it necessarily follows that all the parts of these Spheres undulated through an Homogeneous medium cut the Rays at right angles But because all transparent mediums are not Homogeneous to one another therefore we will next examine how this pulse or motion will be propagated through differingly transparent mediums And here according to the most acute and excellent Philosopher Des Cartes I suppose the sign of the angle of inclination in the first medium to be to the sign of refraction in the second As the density of the first to the density of the second By density I mean not the density in respect of gravity with which the refractions or transparency of mediums hold no proportion but in respect onely to the trajection of the Rays of light in which respect they only differ in this that the one propagates the pulse more easily and weakly the other more slowly but more strongly But as for the pulses themselves they will by the refraction acquire another propriety which we shall now endeavour to explicate We will suppose therefore in the first Figure ACFD to be a physical Ray or ABC and DEF to
be two Mathematical Rays trajected from a very remote point of a luminous body through an Homogeneous transparent medium LLL and DA EB FC to be small portions of the orbicular impulses which must therefore cut the Rays at right angles these Rays meeting with the plain surface NO of a medium that yields an easier transitus to the propagation of light and falling obliquely on it they will in the medium MMM be refracted towards the perpendicular of the surface And because this medium is more easily trajected then the former by a third therefore the point C of the orbicular pulse FC will be mov'd to H four spaces in the same time that F the other end of it is mov'd to G three spaces therefore the whole refracted pulse GH shall be oblique to the refracted Rays CHK and GI and the angle GHC shall be an acute and so much the more acute by how much the greater the refraction be then which nothing is more evident for the sign of the inclination is to be the sign of refraction as GF to TC the distance between the point C and the perpendicular from G on CK which being as four to three HC being longer then GF is longer also then TC therefore the angle GHC is less than GTC. So that henceforth the parts of the pulses GH and IK are mov'd ascew or cut the Rays at oblique angles It is not my business in this place to set down the reasons why this or that body should impede the Rays more others less as why Water should transmit the Rays more easily though more weakly than air Onely thus much in general I shall hint that I suppose the medium MMM to have less of the transparent undulating subtile matter and that matter to be less implicated by it whereas LLL I suppose to contain a greater quantity of the fluid undulating substance and this to be more implicated with the particles of that medium But to proceed the same kind of obliquity of the Pulses and Rays will happen also when the refraction is made out of a more easie into a more difficult mediuÌ„ as by the calculations of GQ CSR which are refracted from the perpendicular In both which calculations 't is obvious to observe that always that part of the Ray towards which the refraction is made has the end of the orbicular pulse precedent to that of the other side And always the oftner the refraction is made the same way Or the greater the single refraction is the more is this unequal progress So that having found this odd propriety to be an inseparable concomitant of a refracted Ray not streightned by a contrary refraction we will next examine the refractions of the Sun-beams as they are suffer'd onely to pass through a small passage obliquely out of a more difficult into a more easie medium Let us suppose therefore ABC in the second Figure to represent a large Chimical Glass-body about two foot long filled with very fair Water as high as AB and inclin'd in a convenient posture with B towards the Sun Let us further suppose the top of it to be cover'd with an opâ—cous body all but the hole ab through which the Sun-beams are suffer'd to pass into the Water and are thereby refracted to cdef against which part if a Paper be expanded on the outside there will appear all the colours of the Rain-bow that is there will be generated the two principal colours Scarlet and Blue and all the intermediate ones which arise from the composition and dilutings of these two that is cd shall exhibit a Scarlet which toward d is diluted into a Yellow this is the refraction of the Ray ik which comes from the underside of the Sun and the Ray ef shall appear of a deep Blue which is gradually towards e diluted into a pale Watchet-blue Between d and e the two diluted colours Blue and Yellow are mixt and compounded into a Green and this I imagine to be the reason why Green is so acceptable a colour to the eye and that either of the two extremes are if intense rather a little offensive namely the being plac'd in the middle between the two extremes and compounded out of both those diluted also or somewhat qualifi'd for the composition arising from the mixture of the two extremes undiluted makes a Purple which though it be a lovely colour and pretty acceptable to the eye yet is it nothing comparable to the ravishing pleasure with which a curious and well tempered Green affects the eye If removing the Paper the eye be plac'd against cd it will perceive the lower side of the Sun or a Candle at night which is much better because it offends not the eye and is more easily manageable to be of a deep Reâ— and if against ef it will perceive the upper part of the luminous body to be of a deep Blue and these colours will appear deeper and deeper according as the Rays from the luminous body fall more obliquely on the surface of the Water and thereby suffer a greater refraction and the more distinct the further cdef is removed from the trajecting hole So that upon the whole we shall find that the reason of the Phaenomena seems to depend upon the obliquity of the orbicular pulse to the Lines of Radiation and in particular that the Ray cd which constitutes the Scarlet has its inner parts namely those which are next to the middle of the luminous body precedent to the outermost which are contiguous to the dark and unradiating skie And that the Ray ef which gives a Blue has its outward part namely that which is contiguous to the dark skie precedent to the pulse from the innermost which borders on the bright area of the luminous body We may observe further that the cause of the diluting of the colours towards the middle proceeds partly from the wideness of the hole through which the Rays pass whereby the Rays from several parts of the luminous body fall upon many of the same parts between c and f as is more manifest by the Figure And partly also from the nature of the refraction it self for the vividness or strength of the two terminating colours arising chiefly as we have seen from the very great difference that is betwixt the outsides of those oblique undulations the dark Rays circumambient and that disparity betwixt the approximate Rays decaying gradually the further inward toward the middle of the luminous body they are remov'd the more must the colour approach to a white or an undisturbed light Upon the calculation of the refraction and reflection from a Ball of Water or Glass we have much the same Phaenomena namely an obliquity of the undulation in the same manner as we have found it here Which because it is very much to our present purpose and affords such an Instancia crucis as no one that I know has hitherto taken notice of I shall further examine For it does
impression on the eye of a Red. But thirdly if the two reflecting surfaces be yet further remov'd asunder ' as in 3 CD and EF are then will the weaker pulse be so farr behind that it will be more then half the distance between cd and cd And in this case it will rather seem to precede the following stronger pulse then to follow the preceding one and consequently a Blue will be generated And when the weaker pulse is just in the middle between two strong ones then is a deep and lovely Purple generated but when the weaker pulse ef is very neer to cd then is there generated a Green which will be bluer or yellower according as the approximate weak pulse does precede or follow the stronger Now fourthly if the thicker Plate chance to be cleft into two thinner Plates as CDFE is devided into two Plates by the surface GH then from the composition arising from the three reflections in the surfaces CD GH and EF there will be generated several compounded or mixt colours which will be very differing according as the proportion between the thicknesses of those two divided Plates CDHG and GHFE are varied And fifthly if these surfaces CD and FE are further remov'd asunder the weaker pulse will yet lagg behind much further and not onely be coincident with the second cd but lagg behind that also and that so much the more by how much the thicker the Plate be so that by degrees it will be coincident with the third cd backward also and by degrees as the Plate grows thicker with a fourth and so onward to a fifth sixth seventh or eighth so that if there be a thin transparent body that from the greatest thinness requisite to produce colours does in the manner of a Wedge by degrees grow to the greatest thickness that a Plate can be of to exhibit a colour by the reflection of Light from such a body there shall be generated several consecutions of colours whose order from the thin end towards the thick shall be Yellow Red Purple Blue Green Yellow Red Purple Blue Green Yellow Red Purple Blue Green Yellow c. and these so often repeated as the weaker pulse does lose paces with its Primary or first pulse and is coincident with a second third fourth fifth sixth c. pulse behind the first And this as it is coincident or follows from the first Hypothesis I took of colours so upon exeriment have I found it in multitudes of instances that seem to prove it One thing which seems of the greatest concern in this Hypothesis is to determine the greatest or least thickness requisite for these effects which though I have not been wanting in attempting yet so exceeding thin are these coloured Plates and so imperfect our Microscope that I have not been hitherto successfull though if my endeavours shall answer my expectations I shall hope to gratifie the curious Reader with some things more remov'd beyond our reach hitherto Thus have I with as much brevity as I was able endeavoured to explicate Hypothetically at least the causes of the Phaenomena I formerly recited on the consideration of which I have been the more particular First because I think these I have newly given are capable of explicating all the Phaenomena of colours not onely of those appearing in the Prisme Water-drop or Rainbow and in laminated or plated bodies but of all that are in the world whether they be fluid or solid bodies whether in thick or thin whether transparent or seemingly opacous as I shall in the next Observation further endeavour to shew And secondly because this being one of the two ornaments of all bodies discoverable by the sight whether looked on with or without a Microscope it seem'd to deserve somewhere in this Tract which contains a description of the Figure and Colour of some minute bodies to be somewhat the more intimately enquir'd into Observ. X. Of Metalline and other real Colours HAving in the former Discourse from the Fundamental cause of Colour made it probable that there are but two Colours and shewn that the Phantasm of Colour is caus'd by the sensation of the oblique or uneven pulse of Light which is capable of no more varieties than two that arise from the two sides of the oblique pulse though each of those be capable of infinite gradations or degrees each of them beginning from White and ending the one in the deepest Scarlet or Yellow the other in the deepest Blue I shall in this Section set down some Observations which I have made of other colours such as Metalline powders tinging or colour'd bodies and several kinds of tinctures or ting'd liquors all which together with those I treated of in the former Observation will I suppose comprise the several subjects in which colour is observ'd to be inherent and the several manners by which it inheres or is apparent in them And here I shall endeavour to shew by what composition all kind of compound colours are made and how there is no colour in the world but may be made from the various degrees of these two colours together with the intermixtures of Black and White And this being so as I shall anon shew it seems an evident argument to me that all colours whatsoever whether in fluid or solid whether in very transparent or seemingly opacous have the same efficient cause to wit some kind of refraction whereby the Rays that proceed from such bodies have their pulse obliquated or confus'd in the manner I explicated in the former Section that is a Red is caus'd by a duplicated or confus'd pulse whose strongest pulse precedes and a weaker follows and a Blue is caus'd by a confus'd pulse where the weaker pulse precedes and the stronger follows And according as these are more or less or variously mixt and compounded so are the sensations and consequently the phantasms of colours diversified To proceed therefore I suppose that all transparent colour'd bodies whether fluid or solid do consist at least of two parts or two kinds of substances the one of a substance of a somewhat differing refraction from the other That one of these substances which may be call'd the tinging substance does consist of distinct parts or particles of a determinate bigness which are disseminated or dispers'd all over the other That these particles if the body be equally and uniformly colour'd are evenly rang'd and dispers'd over the other contiguous body That where the body is deepest ting'd there these particles are rang'd thickest and where 't is but faintly ting'd they are rang'd much thinner but uniformly That by the mixture of another body that unites with either of these which has a differing refraction from either of the other quite differing effects will be produc'd that is the consecutions of the confus'd pulses will be much of another kind and consequently produce other sensations and phantasms of colours and from a Red may turn to a Blue or from a Blue to a Red c.
Their bigness and Figure may be seen in the second Figure of the sixth Plate which represents about a dozen of them lying upon a plate ABCD some of which as a b c d seem'd more regular than the rest and e which was a small one fricking on the top of another was a perfect Rhomboeid on the top and had four Rectagular sides The line E which was the measure of the Microscope is 1 3â— part of an English Inch so that the greatest bredth of any of them exceeded not 1 12â— part of an Inch. Putting these into several liquors I found Oyl of Vitriul Spirit of Vrine and several other Satine menstruâ—ms to dissolve them and the first of these in less than a minute without Ebullition Water and several other liquors had no sudden operation upon them This I mention because those liquors that dissolve them first make them very white not vitiating but rather rectifying their Figure and thereby make them afford a very pretty object for the Microscope How great an advantage it would be to such as are troubled with the Stone to find some menstruum that might dissolve them without hurting the Bladder is easily imagin'd since some injections made of such bodies might likewise dissolve the stone which seems much of the same nature It may therefore perhaps be worthy some Physicians enquiry whether there may not be something mixt with the Urine in which the Gravel or Stone lies which may again make it dissolve it the first of which seems by it's regular Figures to have been sometimes Crystalliz'd out of it For whether this Crystallization be made in the manner as Alum Peter c. are crystallized out of a cooling liquor in which by boyling they have been dissolv'd or whether it be made in the manner of Tartarum Vitriolatum that is by the Coalition of an acid and a Sulphureous substance it seems not impossible but that the liquor it lies in may be again made a dissolvent of it But leaving these inquiries to Physicians or Chymists to whom it does more properly belong I shall proceed Observ. XIII Of the small Diamants or Sparks in Flints CHancing to break a Flint stone in pieces I found within it a certain cavity all crusted over with a very pretty candied substance some of the parts of which upon changing the posture of the Stone in respect of the Incident light exhibited a number of small but very vivid reflections and having made use of my Microscope I could perceive the whole surface of that cavity to be all beset with a multitude of little Crystaline or Adamantine bodies so curiously shap'd that it afforded a not unpleasing object Having considered those vivid repercussions of light I found them to be made partly from the plain external surface of these regularly figured bodies which afforded the vivid reflections and partly to be made from within the somewhat pellucid body that is from some surface of the body opposite to that superficies of it which was next the eye And because these bodies were so small that I could not well come to make Experiments and Examinations of them I provided me several small stiriae of Crystals or Diamants found in great quantities in Cornwall and are therefore commonly called Cornish Diamants these being very pellucid and growing in a hollow cavity of a Rock as I have been several times informed by those that have observ'd them much after the same manner as these do in the Flint and having besides their outward surface very regularly shap'd retaining very near the same Figures with some of those I observ'd in the other became a convenient help to me for the Examination of the properties of those kinds of bodies And first for the Reflections in these I found it very observable That the brightest reflections of light proceeded from within the pellucid body that is that the Rays admitted through the pellucid substance in their getting out on the opposite side were by the contiguous and strong reflecting surface of the Air very vividly reflected so that more Rays were reflected to the eye by this surface though the Ray in entring and getting out of the Crystal had suffer'd a double refraction than there were from the outward surface of the Glass where the Ray had suffer'd no reftraction at all Sche VII And that this was the surface of the Air that gave so vivid a re-percussion I try'd by this means I sunk half of a stiria in Water so that only Water was contiguous to the under surface and then the internal reflection was so exceedingly faint that it was scarce discernable Again I try'd to alter this vivid reflection by keeping off the Air with a body not fluid and that was by rubbing and holding my finger very hard against the under surface so as in many places the pulp of my finger did touch the Glass without any interjacent air between then observing the reflection I found that wheresoever my finger or skin toucht the surface from that part there was no reflection but in the little furrows or creases of my skin where there remain'd little small lines of air from them was return'd a very vivid reflection as before I try'd further by making the surface of very pure Quicksilver to be contiguous to the under surface of this pellucid body and then the reflection from that was so exceedingly more vivid than from the air as the reflection from air was than the reflection from the Water from all which trials I plainly saw that the strong reflecting air was the cause of this Phaenomenon And this agrees very well with the Hypothesis of light and Pellucid bodies which I have mention'd in the description of Muscovy-glass for we there suppose Glass to be a medium which does less resist the pulse of light and consequently that most of the Rays incident on it enter into it and are refracted towards the perpendicular whereas the air I suppose to be a body that does more resist it and consequently more are re-percuss'd then do enter it the same kind of trials have I made with Crystallinâ— Glass with drops of fluid bodies and several other ways which do all seem to agree very exactly with this Theory So that from this Principle well establish'd we may deduce severall Corollaries not unworthy observation And the first is that it plainly appears by this that the production of the Rainbow is as much to be ascribed to the reflection of the concave surface of the air as to the refraction of the Globular drops this will be evidently manifest by these Experiments if you foliate that part of a Glass-ball that is to reflect an Iris as in the Cartesian Experiment above mention'd the reflections will be abundantly more strong and the colours more vivid and if that part of the surface be touch'd with Water scarce affords any sensible colour at all Next we learn that the great reason why pellucid bodies beaten small are white is from the
multitude of reflections not from the particles of the body but from the contiguous surface of the air And this is evidently manifested by filling the Interstitia of those powder'd bodies with Water whereby their whiteness presently disappears From the same reason proceeds the whiteness of many kinds of Sands which in the Microscope appear to be made up of a multitude of little pellucid bodies whose brightest reflections may by the Microscope be plainly perceiv'd to come from their internal surfaces and much of the whiteness of it may be destroy'd by the affusion of fair Water to be contiguous to those surfaces The whiteness also of froth is for the most part to be ascribed to the reflection of the light from the surface of the air within the Bubbles and very little to the reflection from the surface of the Water it self for this last reflection does not return a quarter so many Rays as that which is made from the surface of the air as I have certainly found by a multitude of Observations and Experiments The whiteness of Linnen Paper Silk c. proceeds much from the same reason as the Microscope will easily discover for the Paper is made up of an abundance of pellucid bodies which afford a very plentifull reflection from within that is from the concave surface of the air contiguous to its component particles wherefore by the affusion of Water Oyl Tallow Turpentine c. all those reflections are made more faint and the beams of light are suffer'd to traject run through the Paper more freely Hence further we may learn the reason of the whiteness of many bodies and by what means they may be in part made pellucid As white Marble for instance for this body is composed of a pellucid body exceedingly flaw'd that is there are abundance of thin and very fine cracks or chinks amongst the multitude of particles of the body that contain in them small parcels of air which do so re-percuss and drive back the penetrating beams that they cannot enter very deep within that body which the Microscope does plainly inform us to be made up of a Congeries of pellucid particles And I further found it somewhat more evidently by some attempts I made towards the making transparent Marble for by heating the Stone a little and soaking it in Oyl Turpentine Oyl of Turpentine c I found that I was able to see much deeper into the body of Marble then before and one trial which was not with an unctuous substance succeeded better than the rest of which when I have a better opportunity I shall make further trial This also gives us a probable reason of the so much admired Phaenomena of the Oculus Mundi an Oval stone which commonly looks like white Alabaster but being laid a certain time in Water it grows pellucid and transparent and being suffer'd to lie again dry it by degrees loses that transparency and becomes white as before For the Stone being of a hollow spongie nature has in the first and last of these appearances all those pores fill'd with the obtunding and reflecting air whereas in the second all those pores are fill'd with a medium that has much the same refraction with the particles of the Stone and therefore those two being contiguous make as t were one continued medium of which more is said in the 15. Observation There are a multitude of other Phaenomena that are produc'd from this same Principle which as it has not been taken notice of by any yet that I know so I think upon more diligent observation will it not be found the least considerable But I have here onely time to hint Hypotheses and not to prosecute them so fully as I could with many of them having a vast extent in the production of a multitude of Phaenomena which have been by others either not attempted to be explain'd or else attributed to some other cause than what I have assign'd and perhaps than the right and therefore I shall leave this to the prosecution of such as have more leisure onely before I leave it I must not pretermit to hint that by this Principle multitudes of the Phaenomena of the air as about Mists Clouds Meteors Haloes c. are most plainly and perhaps truly explicable multitudes also of the Phaenomena in colour'd bodies as liquors c. are deducible from it And from this I shall proceed to a second considerable Phaenomenon which these Diamants exhibit and that is the regularity of their Figure which is a propriety not less general than the former It comprising within its extent all kinds of Metals all kinds of Minerals most Precious stones all kinds of Salts multitudes of Earths and almost all kinds of fluid bodies And this is another propiety which though a little superficially taken notice of by some has not that I know been so much as attempted to be explicated by any This propriety of bodies as I think it the most worthy and next in order to be consider'd after the contemplation of the Globular Figure so have I long had a desire as wel as a determination to have prosecuted it if I had had an opportunity having long since propos'd to my self the method of my enquiry therein it containing all the allurements that I think any enquiry is capable of For first I take it to proceed from the most simple principle that any kind of form can come from next the Globular which was therefore the first I set upon and what I have therein perform'd I leave the Judicious Reader to determine For as that form proceeded from a propiety of fluid bodies which I have call'd Congruity or Incongruity so I think had I time and opportunity I could make probable that all these regular Figures that are so conspicuously various and curious and do so adorn and beautifie such multitudes of bodies as I have above hinted arise onely from three or four several positions or postures of Globular particles and those the most plain obvious and necessary conjunctions of such figur'd particles that are possible so that supposing such and such plain and obvious causes concurring the coagulating particles must necessarily compose a body of such a determinate regular Figure and no other and this with as much necessity and obviousness as a fluid body encompast with a Heterogeneous fluid must be protruded into a Spherule or Globe And this I have ad oculum demonstrated with a company of bullets and some few other very simple bodies so that there was not any regular Figure which I have hitherto met withall of any of those bodies that I have above named that I could not with the composition of bullets or globules and one or two other bodies imitate even almost by shaking them together And thus for instance may we find that the Globular bullets will of themselves if put on an inclining plain so that they may run together naturally run into a triangular order composing all the variety of
or fixtness of a body seeming to consist only in this that the one is of a texture or has component parts that will be easily rarify'd into the form of Air and the other that it has such as will not without much ado be brought to such a constitution and this is that part which remains behind in a white body call'd Ashes which contains a substance or Salt which Chymists call Alkali what the particular natures of each of these bodies are I shall not here examine intending it in another place but shall rather add that this Hypothesis does so exactly agree with all Phaenomena of Fire and so genuinely explicate each particular circumstance that I have hitherto observ'd that it is more then probable that this cause which I have assign'd is the true adequate real and onely cause of those Phenomena And therefore I shall proceed a little further to shew the nature and use of the Air. Tenthly therefore the dissolving parts of the Air are but few that is it seems of the nature of those Saline menstruums or spirits that have very much flegme mixt with the spirits and therefore a small parcel of it is quickly glutted and will dissolve no more and therefore unless some fresh part of this menstruum be apply'd to the body to be dissolv'd the action ceases and the body leaves to be dissolv'd and to shine which is the Indication of it though plac'd or kept in the greatest heat whereas Salt-peter is a menstruum when melted and red-hot that abounds more with those Dissolvent particles and therefore as a small quantity of it will dissolve a great sulphureous body so will the dissolution be very quick and violent Therefore in the Eleventh place it is observable that as in other solutions if a copious and quick supply of fresh menstruum though but weak he poured on or applied to the dissoluble body it quickly consumes it So this menstruum of the Air if by Bellows or any other such contrivance it be copiously apply'd to the shining body is found to dissolve it as soon and as violently as the more strong menstruum of melted Nitre Therefore twelfthly it seems reasonable to think that there is no such thing as an Element of Fire that should attract or draw up the flame or towards which the flame should endeavour to ascend out of a desire or appetite of uniting with that as its Homogeneal primitive and generating Element but that that shining transient body which we call Flame is nothing else but a mixture of Air and volatil sulphureous parts of dissoluble or combustible bodies which are acting upon each other whil'st they ascend that is flame seems to be a mixture of Air and the combustible volatil parts of any body which parts the encompassing Air does dissolve or work upon which action as it does intend the heat of the aerial parts of the dissolvent so does it thereby further rarifie those parts that are acting or that are very neer them whereby they growing much lighter then the heavie parts of that Menstruum that are more remote are thereby protruded and driven upward and this may be easily observ'd also in dissolutions made by any other menstruum especially such as either create heat or bubbles Now this action of the Menstuum or Air on the dissoluble parts is made with such violence or is such that it imparts such a motion or pulse to the diaphanous parts of the Air as I have elsewhere shewn is requisite to produce light This Hypothesis I have endeavoured to raise from an Infinite of Observations and Experiments the process of which would be much too long to be here inserted and will perhaps another time afford matter copious enough for a much larger Discourse the Air being a Subject which though all the world has hitherto liv'd and breath'd in and been unconversant about has yet been so little truly examin'd or explain'd that a diligent enquirer will be able to find but very little information from what has been till of late written of it But being once well understood it will I doubt not inable a man to render an intelligible nay probable if not the true reason of all the Phaenomena of Fire which as it has been found by Writers and Philosophers of all Ages a matter of no small difficulty as may be sufficiently understood by their strange Hypotheses and unintelligible Solutions of some few Phaenomena of it so will it prove a matter of no small concern and use in humane affairs as I shall elsewhere endeavour to manifest when I come to shew the use of the Air in respiration and for the preservation of the life nay for the conservation and restauration of the health and natural constitution of mankind as well as all other aereal animals as also the uses of this principle or propriety of the Air in chymical mechanical and other operations In this place I have onely time to hint an Hypothesis which if God permit me life and opportunity I may elsewhere prosecute improve and publish In the mean time before I finish this Discourse I must not forget to acquaint the Reader that having had the liberty granted me of making some trials on a piece of Lignum fossile shewn to the Royal Society by the eminently Ingenious and Learned Physician Doctor Ent who receiv'd it for a Present from the famous Ingenioso Cavalliero de Pozzi it being one of the fairest and best pieces of Lignum fossile he had seen Having I say taken a small piece of this Wood and examin'd it I found it to burn in the open Air almost like other Wood and insteed of a resinous smoak or fume it yielded a very bituminous one smelling much of that kind of sent But that which I chiefly took notice of was that cutting off a small piece of it about the bigness of my Thumb and charring it in a Crucible with Sand after the manner I above prescrib'd I found it infinitely to abound with the smaller sort of pores so extreme thick and so regularly perâ—orating the substance of it long-ways that breaking it off a-cross I found it to look very like an Honey-comb but as for any of the second or bigger kind of pores I could not find that it had any so that it seems whatever were the cause of its production it was not without those small kind of pores which we have onely hitherto found in Vegetable bodies and comparing them with the pores which I have found in the Charcoals that I by this means made of several other kinds of Wood I find it resemble none so much as those of Firr to which it is not much unlike in grain also and several other proprieties Schem X. Observ. XVII Of Petrify'd wood and other Petrify'd bodies OF this sort of substance I observ'd several pieces of very differing kinds both for their outward shape colour grain texture hardness c. some being brown and redish others gray like a Hone others
some Deluge Inundation Earthquake or some such other means came to be thrown to that place and there to be fill'd with some kind of Mudd or Clay or petrifying Water or some other substance which in tract of time has been settled together and hardned in those shelly moulds into those shaped substances we now find them that the great and thin end of these Shells by that Earthquake or what ever other extraordinary cause it was that brought them thither was broken off and that many others were otherwise broken bruised and disfigured that these Shells which are thus spirallied and separated with Diaphragmes were some kind of Nautili or Porcelane shells and that others were shells of Cockles Muscles Periwincles Scolops c. of various sorts that these Shells in many from the particular nature of the containing or enclos'd Earth or some other cause have in tract of time rotted and mouldred away and onely left their impressions both on the containing and contained substances and so left them pretty loose one within another so that they may be easily separated by a knock or two of a Hammer That others of these Shells according to the nature of the substances adjacent to them have by a long continuance in that posture been petrify'd and turn'd into the nature of stone just as I even now observ'd several sorts of Wood to be That oftentimes the Shell may be found with one kind of substance within and quite another without having perhaps been fill'd in one place and afterwards translated to another which I have very frequently observ'd in Cockle Muscle Periwincle and other shells which I have found by the Sea side Nay further that some parts of the same Shell may be fill'd in one place and some other caverns in another and others in a third or a fourth or a fifth place for so many differing substances have I found in one of these petrify'd Shells and perhaps all these differing from the encompassing earth or stone the means how all which varieties may be caus'd I think will not be difficult to conceive to any one that has taken notice of those Shells which are commonly found on the Sea shore And he that shall throughly examine several kinds of such curiously form'd stones will I am very apt to think find reason to suppose their generation or formation to be ascribable to some such accidents as I have mention'd and not to any Plastick virtue For it seems to me quite contrary to the infinite prudence of Nature which is observable in all its works and productions to design every thing to a determinate end and for the attaining of that end makes use of such ways as are as farr as the knowledge of man has yet been able to reach altogether consonant and most agreeable to man's reason and of no way or means that does contradict or is contrary to humane Ratiocination whence it has a long time been a general observation and maxime that Nature does nothing in vain It seems I say contrary to that great Wisdom of Nature that these prettily shap'd bodies should have all those curious Figures and contrivances which many of them are adorn'd and contriv'd with generated or wrought by a Plastick virtue for no higher end then onely to exhibite such a form which he that shall throughly consider all the circumstances of such kind of Figur'd bodies will I think have great reason to believe though I confess one cannot presently be able to find out what Nature's designs are It were therefore very desirable that a good collection of such kind of figur'd stones were collected and as many particulars circumstances and informations collected with them as could be obtained that from such a History of Observations well rang'd examin'd and digested the true original or production of all those kinds of stones might be perfectly and surely known such as are Thunder-stones Lapides Stellares Lapides Iudaici and multitudes of other whereof mention is made in Aldrovandus Wormius and other Writers of Minerals Observ. XVIII Of the Schematisme or Texture of Cork and of the Cells and Pores of some other such frothy Bodies I Took a good clear piece of Cork and with a Pen-knife sharpen'd as keen as a Razor I cut a piece of it off and thereby left the surface of it exceeding smooth then examining it very diligently with a Microscope me thought I could perceive it to appear a little porous but I could not so plainly distinguish them as to be sure that they were pores much less what Figure they were of But judging from the lightness and yielding quality of the Cork that certainly the texture could not be so curious but that possibly if I could use some further diligence I might find it to be discernable with a Microscope I with the same sharp Pen-knife cut off from the former smooth surface an exceeding thin piece of it and placing it on a black object Plate because it was it self a white body and casting the light on it with a deep plano-convex Glass I could exceeding plainly perceive it to be all perforated and porous much like a Honey-comb but that the pores of it were not regular yet it was not unlike a Honey-comb in these particulars First in that it had a very little solid substance in comparison of the empty cavity that was contain'd between as does more manifestly appear by the Figure A and B of the XI Scheme for the Interstitia or walls as I may so call them or partitions of those pores were neer as thin in proportion to their pores as those thin films of Wax in a Honey-comb which enclose and constitute the sexangular cells are to theirs Next in that these pores or cells were not very deep but consisted of a great many little Boxes separated out of one continued long pore by certain Diaphragms as is visible by the Figure B which represents a sight of those pores split the long-ways I no sooner discern'd these which were indeed the first microscopical pores I ever saw and perhaps that were ever seen for I had not met with any Writer or Person that had made any mention of them before this but me thought I had with the discovery of them presently hinted to me the true and intelligible reason of all the Phaenomena of Cork As First if I enquir'd why it was so exceeding light a body my Microscope could presently inform me that here was the same reason evident that there is found for the lightness of froth an empty Honey-comb Wool a Spunge a Pumice-stone or the like namely a very small quantity of a solid body extended into exceeding large dimensions Next it seem'd nothing more difficult to give an intelligible reason why Cork is a body so very unapt to suck and drink in Water and consequently preserves it self floating on the top of Water though left on it never so long and why it is able to stop and hold air in a Bottle though it be
I have almost thought my former observations deficient though indeed upon further examination I have found even those also to confirm them These threads therefore I find to be a congeries of small Laminae or plates as e e e e e c. each of them shap'd much like this of a b c d in the fourth Figure the part a c being a ridge prominency or stem and b and d the corners of two small thin Plates that grow unto the small stalk in the middle so that they make a kind of little feather each of these Plates lie one close to another almost like a company of sloping ridge or gutter Tyles they grow on each side of the stalk opposite to one another by two and two from top to bottom in the manner express'd in the fifth Figure the tops of the lower covering the roots of the next above them the under side of each of these laminated bodies is of a very dark and opacous substance and suffers very few Rays to be trajected but reflects them all toward that side from whence they come much like the foil of a Looking-glass but their upper â—ides seem to me to consist of a multitude of thin plated bodies which are exceeding thin and lie very close together and thereby like mother of Pearl shells do not onely reflect a very brisk light but tinge that light in a most curious manner and by means of various positions in respect of the light they reflect back now one colour and then another and those most vividly Now that these colours are onely fantastical ones that is such as arise immediately from the refractions of the light I found by this that water wetting these colour'd parts destroy'd their colours which seem'd to proceed from the alteration of the reflection and refraction Now though I was not able to see those hairs at all transparent by a common light yet by looking on them against the Sun I found them to be ting'd with a darkish red colour nothing a-kin to the curious and lovely greens and blues they exhibited What the reason of colour seems to be in such thin plated bodies I have elsewhere shewn But how water cast upon those threads destroys their colours I suppose to be perform'd thus The water falling upon these plated bodies from its having a greater congruity to Feathers then the Air insinuates it self between those Plates and so extrudes the strong reflecting Air whence both these parts grow more transparent as the Microscope informs and colourless also at best retaining a very faint and dull colour But this wet being wasted away by the continual evaporations and steams that pass through them from the Peacock whil'st that Bird is yet alive the colours again appear in their former luster the interstitia of these Plates being fill'd with the strongly reflecting Air. The beauteous and vivid colours of the Feathers of this Bird being found to proceed from the curious and exceeding smalness and fineness of the reflecting parts we have here the reason given us of all those gauderies in the apparel of other Birds also and how they come to exceed the colours of all other kinds of Animals besides Insects for since as we here and elsewhere also shew the vividness of a colour depends upon the fineness and transparency of the reflecting and refracting parts and since our Microscope discovers to us that the component parts of feathers are such and that the hairs of Animals are otherwise and since we find also by the Experiment of that Noble and most Excellent Person I formerly named that the difference between Silk and Flax as to its colour is nothing else for Flax reduc'd to a very great fineness of parts both white and colour'd appears as white and as vivid as any Silk but loses that brightness and its Silken aspect as soon as it is twisted into thread by reason that the component parts though very small and fine are yet pliable flakes and not cylinders and thence by twisting become united into one opacous body whereas the threads of Silk and Feathers retain their lustre by preserving their cylindrical form intire without mixing so that each reflected and refracted beam that composes the gloss of Silk preserves its own property of modulating the light intire And since we find the same confirm'd by many other Experiments elsewhere mentioned I think we may safely conclude this for an Axiome that wheresoever we meet with transparent bodies spun out into very fine parts either cleer or any ways ting'd the colours resulting from such a composition must necessarily be very glorious vivid and cleer like those of Silk and Feathers This may perhaps hint some usefull way of making other bodies besides Silk be susceptible of bright tinctures but of this onely by the by The changeable colour'd Feathers also of Ducks and several other Birds I have found by examination with my Microscope to proceed from much the same causes and textures Observ. XXXVII Of the Feet of Flies and several other Insects THe foot of a Fly delineated in the first Figure of the 23. Scheme which represents three joints the two Tallons and the two Pattens in a flat posture and in the second Figure of the same Scheme which represents onely one joint the Tallons and Pattens in another posture is of a most admirable and curious contrivance for by this the Flies are inabled to walk against the sides of Glass perpendicularly upwards and to contain themselves in that posture as long as they please nay to walk and suspend themselves against the under surface of many bodies as the ceiling of a room or the like and this with as great a seeming facility and firmness as if they were a kind of Antipodes and had a tendency upwards as we are sure they have the contrary which they also evidently discover in that they cannot make themselves so light as to stick or suspend themselves on the under surface of a Glass well polish'd and cleans'd their suspension therefore is wholly to be ascrib'd to some Mechanical contrivance in their feet which what it is we shall in brief explain by shewing that its Mechanism consists principally in two parts that is first its two Claws or Tallons and secondly two Palms Pattens or Soles The two Tallons are very large in proportion to the foot and handsomly shap'd in the manner describ'd in the Figures by AB and AC the bigger part of them from A to d d is all hairy or brisled but toward the top at C and B smooth the tops or points which seem very sharp turning downwards and inwards are each of them mov'd on a joint at A by which the Fly is able to open or shut them at pleasure so that the points B and C being entered in any pores and the Fly endeavouring to shut them the Claws not onely draw one against another and so fasten each other but they draw the whole foot GGADD forward so that on a soft
activity cause as great a parcel of Earth to fly on wings in the Air as it does of Water in steams and vapours And what swarms must we suppose to be sent out of those plentifull inundations of water which are poured down by the sluces of Rain in such vast quantities So that we need not much wonder at those innumerable clouds of Locusts with which Africa and other hot countries are so pestred since in those places are found all the convenient causes of their production namely genitors or Parents concurrent receptacles or matrixes and a sufficient degree of natural heat and moisture I was going to annex a little draught of the Figure of those Nuts sent out of Devonshire but chancing to examine Mr. Parkinson's Herbal for something else and particularly about Galls and Oak-apples I found among no less then 24. several kinds of excrescencies of the Oak which I doubt not but upon examination will be all found to be the matrixes of so many several kinds of Insects I having observ'd many of them my self to be so among 24. several kinds I say I found one described and Figur'd directly like that which I had by me the Scheme is there to be seen the description because but short I have here adjoin'd Theatri Botanici trib 16. Chap. 2. There groweth at the roots of old Oaks in the Spring-time and semetimes also in the very heat of Summer a peculiar kind of Mushrom or Excrescence call'd Uva Quercina swelling out of the Earth many growing one close unto another of the fashion of a Grape and therefore took the name the Oak-Grape and is of a Purplish colour on the outside Schem XXVIII and white within like Milk and in the end of Summer becometh hard and woody Whether this be the very same kind I cannot affirm but both the Picture and Description come very neer to that I have but that he seems not to take notice of the hollowness or Worm for which 't is most observable And therefore 't is very likely if men did but take notice they might find very many differing Species of these Nuts Ovaries or Matrixes and all of them to have much the same designation and office And I have very lately found several kinds of Excrescencies on Trees and Shrubs which having endured the Winter upon opening them I found most of them to contain little Worms but dead those things that contain'd them being wither'd and dry Observ. XLIV Of the tusted or Brush-born'd Gnat. THis little creature was one of those multitudes that fill our English air all the time that warm weather lasts and is exactly of the shape of that I observ'd to be generated and hatch'd out of those little Insects that wriggle up and down in Rain-water But though many were of this form yet I observ'd others to be of quite other kinds nor were all of this or the other kind generated out of Water Insects for whereas I observ'd that those that proceeded from those Insects were at their full growth I have also found multitudes of the same shape but much smaller and tenderer seeming to be very young ones creep up and down upon the leaves of Trees and flying up and down in small clusters in places very remote from water and this Spring I oberv'd one day when the Wind was very calm and the afternoon very fair and pretty warm though it had for a long time been very cold weather and the wind continued still in the East several small swarms of them playing to and fro in little clouds in the Sun each of which were not a tenth part of the bigness of one of these I here have delineated though very much of the same shape which makes me ghess that each of those swarms might be the of-spring of one onely Gnat which had been hoorded up in some safe repository all this Winter by some provident Parent and were now by the warmth of the Spring-air hatch'd into little Flies And indeed so various and seemingly irregular are the generations or productions of Insects that he that shall carefully and diligently observe the several methods of Nature therein will have infinitely cause further to admire the wisdom and providence of the Creator for not onely the same kind of creature may be produc'd from several kinds of ways but the very same creature may produce several kinds For as divers Watches may be made out of several materials which may yet have all the same appearance and move after the same manner that is sâ—â—w the hour equally true the one as the other and out of the same kind of matter like Watches may be wrought differing ways and is one and the same Watch may by being diversly agitated or mov'd by this or that agent or after this or that manner produce a quite contrary effect So may it be with these most curious Engines of Insect's bodies the All-wise God of Nature may have so ordered and disposed the little Automatons that when nourished acted or enlivened by this cause they produce one kind of effect or animate shape when by another they act quite another way and another Animal is produc'd So may he so order several materials as to make them by several kinds of methods produce similar Automatons But to come to the Description of this Insect as it appears through a Microscope of which a representation is made in the 28. Scheme It s head A is exceeding small in proportion to its body consisting of two clusters of pearl'd eyes BB on each side of its head whose pearls or eye-balls are curiously rang'd like those of other Flies between these in the forehead of it there are plac'd upon two small black balls CC two long jointed horns tapering towards the top much resembling the long horns of Lobsters each of whose stems or quills DD were brisled or brushed with multitudes of small stiff hairs issuing out every way from the several joints like the strings or sproutings of the herb Horse-tail which is oft observ'd to grow among Corn and for the whole shape it does very much resemble those brushy Vegetables besides these there are two other jointed and brisled horns or feelers EE in the forepart of the head and a proboseis F underneath which in some Gnats are very long streight hollow pipes by which these creatures are able to drill and penetrate the skin and thence through those pipes suck so much bloud as to stuff their bellies so full till they be ready to burst This small head with its appurtenances is fastned on by a short neck G to the middle of the thorax which is large and seems cased with a strong black shel HIK out of the under part of which issue six long and slender legs LLLLLL shap'd just like the legs of Flies but spun or drawn out longer and slenderer which could not be express'd in the Figure because of their great length and from the upper part two oblong but slender transparent wings MM
vanish which by directing a small Telescope towards that part they appear'd and disappeard in I could presently find to be indeed small Starrs so situate as I had seen them with my naked eye and to appear twinkling like the ordinary visible Stars nay in examining some very notable parts of the Heaven with a three foot Tube me thought I now and then in several parts of the constellation could perceive little twinklings of Starrs making a very short kind of apparition and presently vanishing but noting diligently the places where they thus seem'd to play at boe-peep I made use of a very good twelve foot Tube and with that it was not uneasie to see those and several other degrees of smaller Starrs and some smaller yet that seem'd again to appear and disappear and these also by giving the same Object-glass a much bigger aperture I could plainly and constantly see appear in their former places so that I have observ'd some twelve several magnitudes of Starrs less then those of the six magnitudes commonly recounted in the Globes It has been observ'd and confirm'd by the accuratest Observations of the best of our modern Astronomers that all the Luminous bodies appear above the Horizon when they really are below it So that the Sun and Moon have both been seen above the Horizon whil'st the Moon has been in an Eclipse I shall not here instance in the great refractions that the tops of high mountains seen at a distance have been found to have all which seem to argue the Horizontal refraction much greater then it is hitherto generally believ'd I have further taken notice that not onely the Sun Moon and Starrs and high tops of mountains have suffer'd these kinds of refraction but Trees and several bright Objects on the ground I have often taken notice of the twinkling of the reflections of the Sun from a Glass-window at a good distance and of a Candle in the night but that is not so conspicuous and in observing the setting Sun I have often taken notice of the tremulation of the Trees and Bushes as well as of the edges of the Sun Divers of these Phaenomena have been taken notice of by several who have given several reasons of them but I have not yet met with any altogether satisfactory though some of their conjectures have been partly true but parly also false Setting my self therfore upon the inquiry of these Phaenomena I first endeavour'd to be very diligent in taking notice of the several particulars and circumstances observable in them and next in making divers particular Experiments that might cleer some doubts and serve to determine confirm and illustrate the true and adaequate cause of each and upon the whole I find much reason to think that the true cause of all these Phaenomena is from the inflection or multiplicate refraction of those Rays of light within the body of the Atmosphere and that it does not proceed from a refraction caus'd by any terminating superficies of the Air above nor from any such exactly defin'd superficies within the body of the Atmosphere This Conclusion is grounded upon these two Propositions First that a medium whose parts are unequally dense and mov'd by various motions and transpositions as to one another will produce all these visible effects upon the Rays of light without any other coefficient cause Secondly that there is in the Air or Atmosphere such a variety in the constituent parts of it both as to their density and rarity and as to their divers mutations and positions one to another By Density and Rarity I understand a property of a transparent body that does either more or less refract a Ray of light coming obliquely upon its superficies out of a third medium toward its perpendicular As I call Glass a more dense body then Water and Water a more rare body then Glass because of the refractions more or less deflecting towards the perpendicular that are made in them of a Ray of light out of the Air that has the same inclination upon either of their superficies So as to the business of Refraction spirit of Wine is a more dense body then Water it having been found by an accurate Instrument that measures the angles of Refractions to Minutes that for the same refracted angle of 30 00 in both those Mediums the angle of incidence in Water was but 41° 3 ' 5. but the angle of the incidence in the trial with spirit of Wine was 42° 45 ' But as to gravity Water is a more dense body then spirit of Wine for the proportion of the same Water to the same very well rectify'd spirit of Wine was as 21. to 19. So as to Refraction Water is more Dense then Ice for I have found by a most certain Experiment which I exhibited before divers illustrious Persons of the Royal Society that the Refraction of Water was greater then that of Ice though some considerable Authors have affirm'd the contrary and though the Ice be a very hard and the Water a very fluid body That the former of the two preceding Propositions is true may be manifested by several Experiments As first if you take any two liquors differing from one another in density but yet such as will readily mix as Salt Water or Brine Fresh almost any kind of Salt dissolv'd in Water and filtrated so that it be cleer spirit of Wine and Water nay spirit of Wine and spirit of Wine one more highly rectify'd then the other and very many other liquors if I say you take any two of these liquors and mixing them in a Glass Viol against one side of which you have fix'd or glued a small round piece of Paper and shaking them well together so that the parts of them may be somewhat disturb'd and move up and down you endeavour to see that round piece of Paper through the body of the liquors you shall plainly perceive the Figure to wave and to be indented much after the same manner as the limb of the Sun through a Telescope seems to be save onely that the mutations here are much quicker And if in steed of this bigger Circle you take a very small spot and fasten and view it as the former you will find it to appear much like the twinkling of the Starrs though much quicker which two Phaenomena for I shall take notice of no more at present though I could instance in multitudes of others must necessarily be causd by an inflection of the Rays within the terminating superficies of the compounded medium since the surfaces of the transparent body through which the Rays pass to the eye are not at all altered or chang'd This inflection if I may so call it I imagine to be nothing else but a multiplicate refraction caused by the unequal density of the constituent parts of the medium whereby the motion action or progress of the Ray of light is hindred from proceeding in a streight line and inflected or deflected by a curve
agitated undermin'd or heav'd up by eruptions of vapours may naturally be thrown into the same kind of figured holes as the small dust or powder of Alabaster Next it is not improbable but that there may be generated within the body of the Moon divers such kind of internal fires and heats as may produce such Exhalations for since we can plainly enough discover with a Telescope that there are multitudes of such kind of eruptions in the body of the Sun it self which is accounted the most noble Aetherial body certainly we need not be much scandaliz'd at such kind of alterations or corruptions in the body of this lower and less considerable part of the universe the Moon which is only secundary or attendant on the bigger and more considerable body of the Earth Thirdly 't is not unlikely but that supposing such a sandy or mouldring substance to be there found and supposing also a possibility of the generation of the internal elastical body whether you will call it air or vapours 't is not unlikely I say but that there is in the Moon a principle of gravitation such as in the Earth And to make this probable I think we need no better Argument then the roundness or globular Figure of the body of the Moon it self which we may perceive very plainly by the Telescope to be bating the small inequality of the Hills and Vales in it which are all of them likewise shap'd or levelled as it were to answer to the center of the Moons body perfectly of a Sphaerical figure that is all the parts of it are so rang'd bating the comparitively small ruggedness of the Hills and Dales that the outmost bounds of them are equally distant from the Center of the Moon and consequently it is exceedingly probable also that they are equidistant from the Center of gravitation and indeed the figure of the superficial parts of the Moon are so exactly shap'd according as they should be supposing it had a gravitating principle as the Earth has that even the figure of those parts themselves is of sufficient efficacy to make the gravitation and the other two suppositions probable so that the other suppositions may be rather prov'd by this considerable Circumstance or Observation then this suppos'd Explication can by them for he that shall attentively observe with an excellent Telescope how all the Circumstances notable in the shape of the superficial parts are as it were exactly adapted to suit with such a principle will if he well considers the usual method of Nature in its other proceedings find abundant argument to believe it to have really there also such a principle for I could never observe among all the mountainous or prominent parts of the Moon whereof there is a huge variety that any one part of it was plac'd in such a manner that if there should be a gravitating or attracting principle in the body of the Moon it would make that part to fall or be mov'd out of its visible posture Next the shape and position of the parts is such that they all seem put into those very shapes they are in by a gravitating power For first there are but very few clifts or very steep declivities in the ascent of these Mountains for besides those Mountains which are by Hevelius call'd the Apennine Mountains and some other which seem to border on the Seas of the Moon and those only upon one side as is common also in those Hills that are here on the Earth there are very few that seem to have very steep ascents but for the most part they are made very round and much resemble the make of the Hills and Mountains also of the Earth this may be partly perceived by the Hills incompassing this Vale which I have here describ'd and as on the Earth also the middle most of these Hills seems the highest so is it obvious also through a good Telescope in those of the Moon the Vales also in many are much shap'd like those of the Earth and I am apt to think that could we look upon the Earth from the Moon with a good Telescope we might easily enough perceive its surface to be very much like that of the Moon Now whereas in this small draught as there would be multitudes if the whole Moon were drawn after this manner there are several little Ebullitions or Dishes even in the Vales themselves and in the incompassing Hills also this will from this supposition which I have I think upon very good reason taken be exceeding easily explicable for as I have several times also observ'd in the surface of Alabaster so ordered as I before describ'd so may the later eruptions of vapours be even in the middle or on the edges of the former and other succeeding these also in time may be in the middle or edges of these c. of which there are Instances enough in divers parts of the body of the Moon and by a boyling pot of Alabaster will be sufficiently exemplifi'd To conclude therefore it being very probable that the Moon has a principle of gravitation it affords an excellent distinguishing Instance in the search after the cause of gravitation or attraction to hint that it does not depend upon the diurnal or turbinated motion of the Earth as some have somewhat inconsiderately supposed and affirmed it to do for if the Moon has an attractive principle whereby it is not only shap'd round but does firmly contain and hold all its parts united though many of them seem as loose as the sand on the Earth and that the Moon is not mov'd about its Center then certainly the turbination cannot be the cause of the attraction of the Earth and therefore some other principle must be thought of that will agree with all the secundary as well as primary Planets But this I confess is but a probability and not a demonstration which from any Observation yet made it seems hardly capable of though how successful future indeavours promoted by the meliorating of Glasses and observing particular circumstances may be in this or any other kind must be with patience expected FINIS THE TABLE Observat. 1. Of the point of a Needle A Description of it what other Bodies have the sharpest points of the ruggedness of polisht Metal A description of a printed point Of very small writing and the use of it for secret intelligence the cause of the coursness of printed lines and points Observ. 2. Of the Edge of a Razor A description of it the causes of its roughness of the roughness of very well polisht Optick Glasses Obser. 3. Of fine Lawn A description of it A silken Flax mention'd an attempt to explicate the Phaenomena of it with a conjecture at the cause of the gloss of Silk Observ. 4. Of Tabby A short description of it A conjecture about the reason why Silk is so susceptible of vivid colours and why Flax and Hair is not A conjecture that it may perhaps be possible to spin
a kind of artificial Silk out of some glutinous substance that may equalize natural Silk Observ. 5. Of water'd Silks The great unaccurateness of artificial works A description of a piece of water'd Silk an Explication of the cause of the Phaenomena the way by which that operation is perform'd some other Phaenomena mention'd depending on the same cause Observ. 6. Of Glass-Canes The exceeding smalness of some of these Bodies By what means the hollowness of these small pipes was discover'd several Phaenomena of it mention'd An attempt to explicate them from the congruity and incongruity of Bodies what those proprieties are A hypothetical explication of fluidity of the fluidity of the air and several other Phaenomena of it of congruity incongruity illustrated with several Experiments what effects may be ascrib'd to these properties an explication of the roundness of the surface of fluid Bodies how the ingress of fluid bodies into a small hole of an heterogenious body is hindred by incongruity a multitude of Phaenomena explicable hereby Several Quaeries propounded 1. Concerning the propagation of light through differing mediums 2. Concerning Gravity 3. Concerning the roundness of the Sun Moon and Planets 4. Concerning the roundness of Fruits Stones and divers artificial Bodies His Highness Prince Rupert's way of making Shot Of the roundness of Hail Of the grain of Kettering Stone and of the Sparks of fire 5. Concerning springiness and tenacity 6. Concerning the original of Fountains several Histories and Experiments relating thereto 7. Concerning the dissolution of Bodies in Liquors 8. Concerning the universality of this Principle what method was taken in making and applying experiments The explication of filtration and several other Phaenomena such as the motion of Bodies on the surface of Liquors several Experiments mention'd to this purpose Of the height to which the water may rise in these Pipes and a conjecture about the juices of Vegetables the use of their pores A further explication of Congruity And an attempt of solving the Phaenomena of the strange Experiment of the suspension of the Mercury at a much greater height then thirty inches The efficacy of immediate contact and the reason of it Observ. 7. Of Glass drops Several Experiments made with these small Bodies The manner of the breaking and flawing of them explicated by Figures What other bodies will be flawed much in the same manner some other tryals and a description of the Drops themselves some conjectures at the cause of the Phaenomena indeavoured to be made probable by several Arguments and Experiments An Experiment of the expansion of Water by heat and shrinking by cold the like Proprieties suppos'd in Glassdrops and what effects proceed from them the seven Propositions on which the conjectures are grounded Experiments to shew that bodies expand by heat The manner of making Thermometers and the Instrument for graduating them The manner of graduating them and their use Other Experiments to prove the expansion of bodies by heat Four experimental Arguments to prove the expansion of Glass by heat further prov'd by the Experiment of boyling Alabaster which is explicated An explication of the contracting of heated Glass upon cooling An explication how the parts of the Glass become bent by sudden cold and how kept from extricating themselves by the contignation of the Glass drop which is further explicated by another Experiment made with a hollow Glass ball the reason of the flying asunder of the parts further explicated that 't is probable these bodies may have many flaws though not visible and why how a gradual heating and cooling does put the parts of Glass and other hardned bodies into a looser texture Observ. 8. Of Fiery Sparks The occasion and manner of making this Experiment divers Observations set down in order to the finding out the reasons some conjectures concerning it which are endeavoured to be explicated and confirm'd by several Experiments and Reasons the Hypothesis a little further explicated Some Observations about the Globular Figure and an Experiment of reducing the filings of Tin or Lead to exactly round Globules Observ. 9. Of Fantastical Colours The texture of Muscovy Glass its Figures what other Bodies are like it that it exhibits several colours and how several Observations and Experiments about those colours the reason why on this occasion the nature of colours is inquir'd into A conjecture at the reason of these colours explicated by several Experiments and Reasons First by continual cleaving the Body till it become colour'd Secondly by producing all kinds of colours with two flat Plates of Glass Thirdly by blowing Glass so thin in the Lamp till it produce the same effect Fourthly by doing the same with Bubbles of divers other transparent Bodies the reasons of the colours on nealed Steel where by the way the causes of the hardning and tempering of Steel endeavour'd to be shewn and explicated by several Reasons and Experiments the reason of the colours on Lead Brass Copper Silver c. other Instances of such colour'd bodies in animal substances several other distinguishing Observations Des Cartes Hypothesis of Colours examin'd An Hypothesis for the explication of light by motion indeavoured to be explicated and determined by several Reasons and Experiments three distinguishing Properties of the motion of light The distinguishing Properties of a transparent Medium that there seems to be no Experiment that proves the Instantaneous motion of light the manner of the propagation of light through them Of the homogeniety and heterogeniety of transparent Mediums and what effects they cause on the Rayes of light explicated by a Figure an Examination of the refraction of the Rays by a plain Surface which causes Colours An Examination of the like effects produced by a spherical Surface the use that may be made of these Experiments for the examination of several Hyphotheses of Colours Des Cartes Hypothesis examin'd Some Difficulties taken notice of in it What seems most likely to be the cause of colour that propriety is indeavoured to be shewn in a Glass ball that the reflection is not necessary to produce Colours nor a double refraction the Hypothesis further examined both in the pellucid Medium and in the Eye The definitions of Colours and a further explication and examination of the Proprieties of laminated Bodies by what means they conduce to the production of Colours Observ. 10. Of Metalline Colours That all Colours seem to be caus'd by refraction An Hypothesis consonant hereunto explicated by Figures How several Experiments of the sudden changing of Colours by Chymical Liquors may be hereby explicated how many wayes such Chymical Liquors may alter the colours of Bodies Objections made against this Hypothesis of two colours only indeavoured to be answer'd by several Reasons and Experiments The reason why some Colours are capable of being diluted others not what those are that probably the particles of most metalline Colours are transparent for this several Arguments and Observations are recited how Colours become incapable of diluting explicated by
a Similitude An Instrument by which one and the same coloured Liquor at once exhibited all the degrees of colours between the palest yellow and deepest red as likewise another that exhibited all varieties of blues several Experiments try'd with these Boxes An Objection drawn from the nature of Painters colours answered that diluting and whitening a colour are different operations as are deepening and blackening why some may be diluted by grinding and some other by being tempered with Oyl several Experiments for the explicating of some former Assertions why Painters are forced to make use of many colours what those colours are and how mixt The conclusion that most coloured Bodies seem to consist of transparent particles that all colours dissoluble in Liquors are capable of diluting some of mixing what a strange variety may thereby be produc'd Observ. 11. Of the Figures of Sand. Of the substances and shapes of common and other Sands a description of a very small Shell Observ. 12. Of Gravel in Urine A description of such Gravel and some tryals made with it and conjectures at its cause Obser. 13. Of Diamonds in Flints A description and examination of some of them explicated further by Cornish Diamonds several Observations about reflection and refraction and some deductions therefrom as an explication of whiteness that the Air has a stronger reflection then Water How several Bodies may be made transparent an explication of the Phaenomena of Oculus Mundi Of the regular Geometrical Figures of several Bodies an hypothetical explication mentioned the method of prosecuting this inquiry Observ 14. Of frozen Figure The Figures of hoar Frost and the Vertices on windows several Observations on the branched Figures of Vrine the Figures of Regulus Martis stellatus and of Fern. Of the Figures of Snow Of frozen water Observ. 15. Of Kettering Stone A description of the Figure of the Particles and of the Pores and of the Contexture Several Observations and Considerations thereupon some Conjectures about the medium and propagation of light and the constitution of fluid and transparent Bodies Several Experiments to prove the porousness of â—Marble and some other Stones An account of some Experiments to this purpose made on an Oculus Mundi some other Considerations and Experiments about the porousness of Bodies some other Considerations about the propagation of light and refraction Observ. 16. Of Charcoal Of two sort of Pores to be found in all Woods and Vegetables the shape of them the number thickness manner and use of these Pores An explication of the Phaenomena of Coals The manner of charring Wood or any other body What part of Wood is combustible An Hypothesis of fire explicated in twelve particulars wherein the Action of the Air as a Menstruum in the dissolution of all sulphureous bodies is very particularly explicated and some other Considerations about the Air proposed the examination of a piece of Lignum fossile sent from Rome and some Conclusions thence deduc'd Observ. 17. Of Wood and other Bodies petrified Several Observations of divers kinds of these substances A more particular examination and explication of one very notable piece of petrified Wood and some Conjectures about the cause of those productions several Observations made on other petrified Bodies as Shells c. And some probable Conclusions thence deduc'd about the original cause of those Bodies Observ. 18. Of the Pores of Cork and other Bodies Several Observations and Considerations about the nature of Cork the number of Pores in a cubical Inch and several Considerations about Pores Several Experiments and Observations about the nature of Cork the Texture and Pores of the Pith of an Elder and several other Trees of the Stalks of Burdocks Teasels Daisies Carret Fennel Ferne Reeds c. of the frothy texture of the Pith of a Feather some Conjectures about the probability of values in these Pores Argued also from the Phaenomena of the sensible and humble Plant some Observations on which are inserted Observ. 19. Of a Vegetable growing on blighted Leaves Several Observations and Examinations made of them several Considerations about spontaneous generation arising from the putrefaction of Bodies Observ. 20. Of Blew Mould and Mushromes The description of several kinds of Moulds The method of proceeding in natural Inquiries Several Considerations about the nature of Mould and Mushromes 1. That they may be produc'd without seed 2. That they seem to have none 3. That Salts c. are shap'd into as curious figures without a seed 4. Of a kind of Mushrome growing in a Candle A more particular explication of this last sort of Mushromes 5. Of the figure and manner of the production of petrified Iceicles several deductions from these Considerations about the nature of the vegetation of Mould and Mushromes Observ. 21. Of Moss The description of several sorts of Mosses upon this occasion several Conjectures about the manner of the production of these kinds of Bodies are hinted and some of them explicated by a Similitude taken from a piece of Clock-work The vast difference of the bigness of vegetable Bodies and the probability that the least may comprehend as curious contrivances as the greatest Of multitudes of other Moulds Mosses and Mushromes and other vegetating Principles in Water Wood c. Observ. 22. Of Sponges and other fibrous Bodies Several Observations and Conjectures about the making of these Bodies and several Histories out of Authors Scarce any other Body hath such a texture the fibrous texture of Leather Spunk c. which are there describ'd come nearest to it That upon tryal with a piece of Spunge and Oyl the necessity of respiration could not be alter'd Observ. 23. Of the Form of Sea-weed From the curiously shap'd Surface of this Sea-weed and some others is conjectured the possibility of multitudes of the like Observ. 24. Of the Surfaces of some Leaves The description 1. Of the bald Surfaces of Leaves 2. Of the downy Surfaces of several others 3. Of the gummous exsudation or small transparent Pearls discovered with a Microscope in several others An Instance of all which is afforded in a Rosemary Leaf Observ. 25. Of the stinging Points of a Nettle A description of the Needles and several other contrivances in the leaf of a Nettle how the stinging pain is created upon this several considerations about poysoning Darts are set down An Experiment of killing Effs and Fishes with Salt Some conjectures at the efficacy of Baths the use that may be made of injecting into the Veins A very remarkable History out of Bellonius and some Considerations about staining and dying of Bodies Observ. 26. Of Cowage The description of it out of Parkinson an Experiment made of it a description and some conjectures at the cause of the Phaenomena Observ. 27. Of the Beard of a wild Oat The description of its shape and properties the manner of making a Hygroscope with it and a Conjecture at the causes of these motions and of the motions of the Muscles Observ. 28. Of the Seeds
or any other creatures seeking and placing their Seeds in convenient repositories we may if we attentively consider and examine it find that there are circumstances sufficient upon the supposals of the excellent contrivance of their machine to excite and force them to act after such or such a manner those steams that rise from these several places may perhaps set several parts of these little Animals at work even as in the contrivance of killing a Fox or Wolf with a Gun the moving of a string is the death of the Animal for the Beast by moving the flesh that is laid to entrap him pulls the string which moves the trigger and that le ts go the Cock which on the steel strikes certain sparks of fire which kindle the powder in the pann and that presently flies into the barrel where the powder catching fire ratifies and drives out the bullet which kills the Animal in all which actions there is nothing of intention or ratiocination to be ascrib'd either to the Animal or Engine but all to the ingeniousness of the contriver But to return to the more immediate consideration of our Gnat We have in it an Instance not usual or common of a very stange amphibious creature that being a creature that inhabits the Air does yet produce a creature that for some time lives in the water as a Fish though afterward which is as strange it becomes an inhabitant of the Air like its Sire in the form of a Fly And this me thinks does prompt me to propose certain conjectures as Queries having not yet had sufficient opportunity and leisure to answer them my self from my own Experiments or Observations And the first is Whether all those things that we suppose to be bred from corruption and putrifaction may not be rationally suppos'd to have their origination as natural as these Gnats who 't is very probable were first dropt into this Water in the form of Eggs. Those Seeds or Eggs must certainly be very small which so small a creature as a Gnat yields and therefore we need not wonder that we find not the Eggs themselves some of the younger of them which I have observ'd having not exceeded a tenth part of the bulk they have afterwards come to and next I have observed some of those little ones which must have been generated after the Water was inclosed in the Bottle and therefore most probably from Eggs whereas those creatures have been suppos'd to be bred of the corruption of the Water there being not formerly known any probable way how they should be generated A second is whether these Eggs are immediately dropt into the Water by the Gnats themselves or mediately are brought down by the falling rain for it seems not very improbable but that those small seeds of Gnats may being perhaps of so light a nature and having so great a proportion of surface to so small a bulk of body be ejected into the Air and so perhaps carried for a good while too and fro in it till by the drops of Rain it be wash'd out of it A third is whether multitudes of those other little creatures that are found to inhabit the Water for some time do not at certain times take wing and fly into the Air others dive and hide themselves in the Earth and so contribute to the increase both of the one and the other Element Postscript A good while since the writing of this Description I was presented by Doctor Peter Ball an ingenious Member of the Royal Society with a little Paper of Nuts which he told me was sent him from a Brother of his out of the Countrey from Mamhead in Devonshire some of them were loose having been as I suppose broken off others were still growing fast on upon the sides of a stick which seem'd by the bark pliableness of it and by certain strings that grew out of it to be some piece of the root of a Tree they were all of them dry'd and a little shrivell'd others more round of a brown colour their shape was much like a Figg but very much smaller some being about the bigness of a Bay-berry others and the biggest of a Hazel-Nut Some of these that had no hole in them I carefully opened with my Knife and found in them a good large round white Maggot almost as bigg as a small Pea which seem'd shap'd like other Maggots but shorter I could not find them to move though I ghess'd them to be alive because upon pricking them with a Pinn there would issue out a great deal of white mucous matter which seem'd to be from a voluntary contraction of their skin their husk or matrix consisted of three Coats like the barks of Trees the outermost being more rough and spongie and the thickest the middlemost more close hard white and thin the innermost very thin seeming almost like the skin within an Egg 's shell The two outermost had root in the branch or stick but the innermost had no stem or process but was onely a skin that cover'd the cavity of the Nut. All the Nuts that had no holes eaten in them I found to contain these Maggots but all that had holes I found empty the Maggots it seems having eaten their way through taken wings and flown away as this following account which I receiv'd in writing from the same person as it was sent him by his Brother manifests In a moorish black Peaty mould with some small veins of whitish yellow Sands upon occasion of digging a hole two or three foot deep at the head of a Pond or Pool to set a Tree in at that depth were found about the end of October 1663. in those very veins of Sand those Buttons or Nuts sticking to a little loose stick that is not belonging to any live Tree and some of them also free by themselves Four or five of which being then open'd some were found to contvin live Insects come to perfection most like to flying Ants if not the same in others Insects yet imperfect having but the head and wings form'd the rest remaining a soft white pulpy substance Now as this furnishes us with one odd History more very agreeable to what I before hinted so I doubt not but were men diligent observers they might meet with multitudes of the same kind both in the Earth and in the Water and in the Air on Trees Plants and other Vegetables all places and things being as it were animarum plena And I have often with wonder and pleasure in the Spring and Summer-time look'd close to and diligently on common Garden mould and in a very small parcel of it found such multitudes and diversities of little reptiles some in husks others onely creepers many wing'd and ready for the Air divers husks or habitations left behind empty Now if the Earth of our cold Climate be so fertile of animate bodies what may we think of the fat Earth of hotter Climates Certainly the Sun may there by its
of Venice Looking-glass The description of them Obser. 29. Of the Seeds of Time A description of them A digression about Natures method Observ. 30. Of Poppy Seeds The description and use of them Observ. 31. Of Purslane Seeds A description of these and many other Seeds Observ. 32. Of Hair The description of several sorts of Hair their Figures and Textures the reason of their colours A description of the texture of the skin and of Spunk and Sponges by what passages and pores of the skin transpiration seems to be made Experiments to prove the porousness of the skin of Vegetables Observ. 33. Of the Scales of a Soale A description of their beauteous form Observ. 34. Of the Sting of a Bee A description of its shape mechanisme and use Observ. 35. Of Feathers A description of the shape and curious contexture of Feathers and some conjectures thereupon Obser. 36. Of Peacocks Feathers A description of their curious form and proprieties with a conjecture at the cause of their variable colours Obser. 37. Of the Feet of Flyes and other Insects A description of their figure parts and use and some considerations thereupon Obser. 38. Of the Wings of Flyes After what manner and how swiftly the wings of Insects move A description of the Pendulums under the wings and their motion the shape and structure of the parts of the wing Obser. 39 Of the Head of a Fly 1. All the face of a Drone-fly is nothing almost but eyes 2. Those are of two magnitudes 3. They are Hemispheres and very reflective and smooth 4. Some directed towards every quarter 5. How the Fly cleanses them 6. Their number 7. Their order divers particulars observ'd in the dissecting a head That these are very probably the eyes of the Creature argued from several Observations and Experiments that Crabs Lobsters Shrimps seem to be water Insects and to be framed much like Air Insects Several Considerations about their manner of vision Obser. 40. Of the Teeth of a Snail A brief description of it Observ. 41. Of the Eggs of Silk-worms Several Observables about the Eggs of Insects Observ. 42. Of a blue Fly A description of its outward and inward parts It s hardiness to indure freezing and steeping in Spirit of wine Observ. 43. Of a water Insect A description of its shape transparency motion both internal and progressive and transformation A History somewhat Analogus cited out of Piso. Several Observations about the various wayes of the generations of Insects by what means they act so seemingly wisely and prudently Several Quaeries propounded Postscript containing a relation of another very odd way of the generation of Insects An Observation about the fertility of the Earth of our Climate in producing Insects and of divers other wayes of their generation Observ. 44. Of the tufted Gnat. Several Observables about Insects and a more particular description of the parts of this Gnat. Ob. 45. Of the great belly'd Gnat. A short description of it Obser. 46. Of a white Moth. A description of the feathers and wings of this and several other Insects Divers Considerations about the wings and the flying of Insects and Birds Obs. 47. Of the Shepherd Spider A description of its Eyes and the sockets of its long legs and a Conjecture of the mechanical reason of its fabrick together with a supposition that 't is not unlikely but Spiders may have the make of their inward parts exactly like a Crab which may be call'd a water Spider Obser. 48. Of the hunting Spider A short description of it to which is annext an excellent History of it made by Mr. Evelyn Some further Observations on other Spiders and their Webs together with an examination of a white Substance flying up and down in the Air after a Fog Obser. 49. Of an Ant. That all small Bodies both Vegetable and Animal do quickly dry and wither The best remedy I found to hinder it and to make the Animal lye still to be observ'd Several particulars related of the actions of this Creature and a short description of its parts Obs. 50. Of the wandring Mite A description of this Creature and of another very small one which usually bore it company A Conjecture at the original of Mites Observ. 51. Of a Crab-like Insect A brief description of it Observ. 52. Of a Book-worm A description of it where by the way is inserted a digression experimentally explicating the Phaenomena of Pearl A consideration of its digestive faculty Observ. 53. Of a Flea A short description of it Observ. 54. Of a Louse A description of its parts and some notable circumstances Observ. 55. Of Mites The exceeding smalness of some Mites and their Eggs. A description of the Mites of Cheese and an intimation of the variety of forms in other Mites with a Conjecture at the reason Ob. 56. Of small Vine-Mites A description of them a ghess at their original their exceeding smalness compar'd with that of a Wood-louse from which they may be suppos'd to come Observ. 57. Of Vinegar-worms A description of them with some considerations on their motions Obs. 58. Of the Inflection of the Rays of Light in the Air. A short rehearsal of several Phaenomena An attempt to explicate them the supposition founded on two Propositions both which are indeavoured to be made out by several Experiments What density and rarity is in respect of refraction the refraction of Spirit of Wine compared with that of common Water the refraction of Ice An Experiment of making an Vndulation of the Rays by the mixing of Liquors of differing density The explication of inflection mechanically and hypothetically what Bodies have such an inflection Several Experiments to shew that the Air has this propriety that it proceeds from the differing density of the Air that the upper and under part of the Air are of differing density some Experiments to prove this A Table of the strength of the spring of the Air answering to each degree of extension when first made and when repeated Another Experiment of compressing the Air. A Table of the strength of the Air answering to each compression and expansion from which the height of the Air may be suppos'd indefinite to what degree the Air is rarifi'd at any distance above the Surface of the Earth how from this Inflection is inferr'd and several Phaenomena explain'd That the air near the Earth is compos'd of parts of differing density made probable by several Experiments and Observations how this propriety produces the effects of the waving and dancing of Bodies and of the twinkling of the Stars Several Phaenomena explicated Some Quoeries added 1. Whether this Principle may not be made use of for perfecting Optick Glasses What might be hoped from it if it were to be done 2. Whether from this Principle the apparition of some new Stars may not be explicated 3. Whether the height of the Air may be defin'd by it 4. Whether there may not sometimes be so great a disparity of density between