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
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
perceive the perforation with ones naked eye though by the help of a Microscope it may easily enough be perceived Nay I have made a Pipe perforated from end to end so small that with my naked eye I could very hardly see the body of it insomuch that I have been able to knit it up into a knot without breaking And more accurately examining one with my Microscope I found it not so big as a sixteenth part of one of the smaller hairs of my head which was of the smaller and finer sort of hair so that sixteen of these Pipes bound faggot-wiâ—e together would but have equalized one single hair how small therefore must its perforation be It appearing to me through the Microscope to be a proportionably thick-sided Pipe To proceed then for the trial of the Experiment the Experimenter must place the Tube AB perpendicular and fill the Pipe F cemented into the hole E with water but leave the bubble C full of Air and then gently pouring in water into the Pipe AB he must observe diligently how high the water will rise in it before it protrude the bubble of Air C through the narrow passage of F and denote exactly the height of the Cylinder of water then cementing in a second Pipe as G and filling it with water he may proceed as with the former denoting likewise the height of the Cylinder of water able to protrude the bubble C through the passage of G the like may he do with the next Pipe and the next c. as far as he is able then comparing the several heights of the Cylinders with the several holes through which each Cylinder did force the air having due regard to the Cylinders of water in the small Tubes it will be very easie to determine what force is requisite to press the Air into such and such a hole or to apply it to our present experiment how much of the pressure of the Air is taken off by its ingress into smaller and smaller holes From the application of which to the entring of the Air into the bigger hole of the Vessel and into the smaller hole of the Pipe we shall clearly find that there is a greater pressure of the air upon the water in the Vessel or greater pipe then there is upon that in the lesser pipe For since the pressure of the air every way is found to be equal that is as much as is able to press up and sustain a Cylinder of Quicksilver of two foot and a half high or thereabouts And since of this pressure so many more degrees are required to force the Air into a smaller then into a greater hole that is full of a more congruous fluid And lastly since those degrees that are requisite to press it in are thereby taken off from the Air within and the Air within left with so many degrees of pressure less then the Air without it will follow that the Air in the less Tube or pipe will have less pressure against the superficies of the water therein then the Air in the bigger which was the minor Proposition to be proved The Conclusion therefore will necessarily follow viz. That this unequal pressure of the Air caused by its ingress into unequal holes is a cause sufficient to produce this effect without the help of any other concurrent and therefore is probably the principal if not the only cause of these Phaenomena This therefore being thus explained there will be divers Phaenomena explicable thereby as the rising of Liquors in a Filtre the rising of Spirit of Wine Oyl melted Tallow c. in the Week of a Lamp though made of small Wire Threeds of Asbestus Strings of Glass or the like the rising of Liquors in a Spunge piece of Bread Sand c. perhaps also the ascending of the Sap in Trees and Plants through their small and some of them imperceptible pores of which I have said more on another occasion at least the passing of it out of the earth into their roots And indeed upon the consideration of this Principle multitudes of other uses of it occurr'd to me which I have not yet so well examined and digested as to propound for Axioms but only as Queries and Conjectures which may serve as hints toward some further discoveries As first Upon the consideration of the congruity and incongruity of Bodies as to touch I found also the like congruity and incongruity if I may so speak as to the Transmitting of the Raies of Light For as in this regard water not now to mention other Liquors seems nearer of affinity to Glass then Air and Air then Quicksilver whence an oblique Ray out of Glass will pass into water with very little refraction from the perpendicular but none out of Glass into Air excepting a direct will pass without a very great refraction from the perpendicular nay any oblique Ray under thirty degrees will not be admitted into the Air at all And Quicksilver will neither admit oblique or direct but reflects all seeming as to the transmitting of the Raies of Light to be of a quite differing constitution from that of Air Water Glass c. and to resemble most those opacous and strong reflecting bodies of Metals So also as to the property of cohesion or congruity Water seems to keep the same order being more congruous to Glass then Air and Air then Quicksilver A Second thing which was hinted to me by the consideration of the included fluids globular form caused by the protrusion of the ambient heterogeneous fluid was whether the Phaenomena of gravity might not by this means be explained by supposing the Globe of Earth Water and Air to be included with a fluid heterogeneous to all and each of them so subtil as not only to be every where interspersed through the Air or rather the air through it but to pervade the bodies of Glass and even the closest Metals by which means it may endeavour to detrude all earthly bodies as far from it as it can and partly thereby and partly by other of its properties may move them towards the Center of the Earth Now that there is some such fluid I could produce many Experiments and Reasons that do seem to prove it But because it would ask some time and room to set them down and explain them and to consider and answer all the Objections many whereof I foresee that may be alledged against it I shall at present proceed to other Queries contenting my self to have here only given a hint of what I may say more elswhere A Third Query then was Whether the heterogeneity of the ambient fluid may not be accounted a secondary cause of the roundness or globular form of the greater bodies of the world such as are those of the Sun Stars and Planets the substance of each of which seems altogether heterogeneous to the circum-ambient fluid aether And of this I shall say more in the Observation of the Moon A Fourth was
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
find the like effects produced and in general wheresoever you meet with a transparent body thin enough that is terminated by reflecting bodies of differing refractions from it there will be a production of these pleasing and lovely colours Nor is it necessary that the two terminating Bodies should be both of the same kind as may appear by the vitrified Laminae on Steel Lead and other Metals one surface of which Laminae is contiguous to the surface of the Metal the other to that of the Air. Nor is it necessary that these colour'd Laminae should be of an even thickness that is should have their edges and middles of equal thickness as in a Looking-glass-plate which circumstance is only requisite to make the Plate appear all of the same colour but they may resemble a Lens that is have their middles thicker then their edges or else a double concave that is be thinner in the middle then at the edges in both which cases there will be various coloured rings or lines with differing consecutions or orders of Colours the order of the first from the middle outwards being Red Yellow Green Blew c. And the latter quite contrary But further it is altogether necessary that the Plate in the places where the Colours appear should be of a determinate thickness First It must not be more then such a thickness for when the Plate is increased to such a thickness the Colours cease and besides I have seen in a thin piece of Muscovy-glass where the two ends of two Plates which appearing both single exhibited two distinct and differing Colours but in that place where they were united and constituted one double Plate as I may call it they appeared transparent and colourless Nor Secondly may the Plates be thinner then such a determinate cize for we alwayes find that the very outmost Rim of these flaws is terminated in a white and colourless Ring Further in this Production of Colours there is no need of a determinate Light of such a bigness and no more nor of a determinate position of that Light that it should be on this side and not on that side nor of a terminating shadow as in the Prisme and Rainbow or Water-ball for we find that the Light in the open Air either in or out of the Sun-beams and within a Room either from one or many Windows produces much the same effect only where the Light is brightest there the Colours are most vivid So does the light of a Candle collected by a Glass-ball And further it is all one whatever side of the coloured Rings be towards the light for the whole Ring keeps its proper Colours from the middle outwards in the same order as I before related without varying at all upon changing the position of the light But above all it is most observable that here are all kind of Colours generated in a pellucid body where there is properly no such refraction as Des Cartes supposes his Globules to acquire a verticity by For in the plain and even Plates it is manifest that the second refraction according to Des Cartes his Principles in the fifth Section of the eighth Chapter of his Meteors does regulate and restore the supposed turbinated Globules unto their former uniform motion This Experiment therefore will prove such a one as our thrice excellent Verulam calls Experimentum Crucis serving as a Guide or Land-mark by which to direct our course in the search after the true cause of Colours Affording us this particular negative Information that for the production of Colours there is not necessary either a great refraction as in the Prisme nor Secondly a determination of Light and shadow such as is both in the Prisme and Glass-ball Now that we may see likewise what affirmative and positive Instruction it yields it will be necessary to examine it a little more particularly and strictly which that we may the better do it will be requisite to premise somewhat in general concerning the nature of Light and Refraction And first for Light it seems ' very manifest that there is no luminous Body but has the parts of it in motion more or less First That all kind of fiery burning Bodies have their parts in motion I think will be very easily granted me That the spark struck from a Flint and Steel is in a rapid agitation I have elsewhere made probable And that the Parts of rotten Wood rotten Fish and the like are also in motion I think will as easily be conceded by those who consider that those parts never begin to shine till the Bodies be in a state of putrefaction and that is now generally granted by all to be caused by the motion of the parts of putrifying bodies That the Bononian stone shines no longer then it is either warmed by the Sun-beams or by the flame of a Fire or of a Candle is the general report of those that write of it and of others that have seen it And that heat argues a motion of the internal parts is as I said before generally granted But there is one Instance more which was first shewn to the Royal Society by Mr. Clayton a worthy Member thereof which does make this Assertion more evident then all the rest And that is That a Diamond being rub'd struck or beated in the dark shines for a pretty while after so long as that motion which is imparted by any of those Agents remains in the same manner as a Glass rubb'd struck or by a means which I shall elsewhere mention heâ—â—ed yields a sound which lasts as long as the vibrating motion of that sonorous body several Experiments made on which Stone are since published in a Discourse of Colours by the truly honourable Mr. Boyle What may be said of those Ignes fatus that appear in the night I cannot so well affirm having never had the opportunity to examine them my self nor to be inform'd by any others that had observ'd them And the relations of them in Authors are so imperfect that nothing can be built on them But I hope I shall be able in another place to make it at least very probable that there is even in those also a Motion which causes this effect That the shining of Sea-water proceeds from the same cause may be argued from this That it shines not till either it be beaten against a Rock or be some other wayes broken or agitated by Storms or Oars or other pereussing bodies And that the Animal Energyes or Spirituous agil parts are very active in Cats eyes when they shine seems evident enough because their eyes never shine but when they look very intensly either to find their prey or being hunted in a dark room when they seek after their adversary or to find a way to escape And the like may be said of the shining Bellies of Gloworms since 't is evident they can at pleasure either increase or extinguish that Radiation It would be somewhat too long a work for
and those subcollateral and those latero subcollateral c. and all those much after the same order with the branchings divisions and subdivisions in the branchings of these Figures in frozen Vrine so that if the Figures of both be well consider'd one would ghess that there were not much greater need of a seminal principle for the production of Fearn then for the production of the branches of Vrine or the Stella martis there seeming to be as much form and beauty in the one as in the other And indeed this Plant of Fearn if all particulars be well consider'd will seem of as simple and uncompounded a form as any Vegetable next to Mould or Mushromes and would next after the invention of the forms of those deserve to be enquir'd into for notwithstanding several have affirm'd it to have seed and to be propagated thereby yet though I have made very diligent enquiry after that particular I cannot find that there is any part of it that can be imagin'd to be more seminal then another But this onely here by the by For the freezing Figures in Vrine I found it requisite First that the Superficies be not disturbed with any wind or other commotion of the air or the like Secondly that it be not too long exposed so as that the whole bulk be frozen for oftentimes in such cases by reason of the swelling the of Ice or from some other cause the curious branched Figures disappear Thirdly an artificial freezing with Snow and Salt apply'd to the outside of the containing Vessel succeeds not well unless there be a very little quantity in the Vessel Fourthly If you take any cleer and smooth Glass and wetting all the inside of it with Vrine you expose it to a very sharp freezing you will find it cover'd with a very regular and curious Figure II. Observables in figur'd Snow Exposing a piece of black Cloth or a black Hatt to the falling Snow I have often with great pleasure observ'd such an infinite variety of curiously figur'd Snow that it would be as impossible to draw the Figure and shape of every one of them as to imitate exactly the curious and Geometrical Mechanisme of Nature in any one Some coorse draughts such as the coldness of the weather and the ill provisions I had by me for such a purpose would permit me to make I have here added in the Second Figure of the Eighth Scheme In all which I observ'd that if they were of any regular Figures they were always branched out with six principal branches all of equal length shape and make from the center being each of them inclin'd to either of the next branches on either side of it by an angle of sixty degrees Now as all these stems were for the most part in one flake exactly of the same make so were they in differing Figures of very differing ones so that in a very little time I have observ'd above an hundred several cizes and shapes of these starry flakes The branches also out of each stem of any one of these flakes were exactly alike in the same flake so that of whatever Figure one of the branches were the other five were sure to be of the same very exactly that is if the branchings of the one were small Perallelipipeds or Plates the branchings of the other five were of the same and generally the branchings were very conformable to the rules and method observ'd before in the Figures on Vrine that is the branchings from each side of the stems were parallel to the next stem on that side and if the stems were plated the branches also were the same if the stems were very long the branches also were so c. Observing some of these figur'd flakes with a Microscope I found them not to appear so curious and exactly figur'd as one would have imagin'd but like Artificial Figures the bigger they were magnify'd the more irregularites appear'd in them but this irregularity seem'd ascribable to the thawing and breaking of the flake by the fall and not at all to the defect of the plastick virtue of Nature whose curiosity in the formation of most of these kind of regular Figures such as those of Salt Minerals c. appears by the help of the Microscope to be very many degrees smaller then the most acute eye is able to perceive without it And though one of these six-branched Stars appear'd here below much of the shape described in the Third Figure of the Eighth Scheme yet I am very apt to think that could we have a sight of one of them through a Microscope as they are generated in the Clouds before their Figures are vitiated by external accidents they would exhibit abundance of curiosity and neatness there also though never so much magnify'd For since I have observ'd the Figures of Salts and Minerals to be some of them so exceeding small that I have scarcely been able to perceive them with the Microscope and yet have they been regular and since as far as I have yet examin'd it there seems to be but one and the same cause that produces both these effects I think it not irrational to suppose that these pretty figur'd Stars of Snow when at first generated might be also very regular and exact III. Several kinds of Figures in Water frozen Putting fair Water into a large capacious Vessel of Glass and exposing it to the cold I observ'd after a little time several broad flat and thin laminae or plates of Ice crossing the bulk of the water and one another very irregularly onely most of them seem'd to turn one of their edges towards that side of the Glass which was next it and seem'd to grow as 't were from the inside of the Vessel inwards towards the middle almost like so many blades of Fern. Having taken several of these plates out of water on the blade of a Knife I observ'd them figur'd much after the manner of Herring bones or Fern blades that is there was one bigger stem in the middle like the back-bone and out of it on either side were a multitude of small stiriae or icicles like the smaller bones or the smaller branches in Fern each of these branches on the one side were parallel to all the rest on the same side and all of them seem'd to make an angle with the stem towards the top of sixty degrees and towards the bottom or root of this stem of 120. See the fourth Figure of the 8. Plate I observ'd likewise several very pretty varieties of Figures in Water frozen on the top of a broad flat Marble-stone expos'd to the cold with a little Water on it some like feathers some of other shapes many of them were very much of the shape exprest in the fifth Figure of the 8. Scheme which is extremely differing from any of the other Figures I observ'd likewise that the shootings of Ice on the top of Water beginning to freez were in streight prismatical
through the leaves and covers it appears to the naked eye a small glistering Pearl-colour'd Moth which upon the removing of Books and Papers in the Summer is often observ'd very nimbly to scud and pack away to some lurking cranney where it may the better protect it self from any appearing dangers It s head appears bigg and blunt and its body tapers from it towards the tail smaller and smaller being shap'd almost like a Carret This the Microscopical appearance will more plainly manifest which exhibits in the third Figure of the 33. Scheme a conical body divided into fourteen several partitions being the appearance of so many several shels or shields that cover the whole body every of these shells are again cover'd or tiled over with a multitude of thin transparent scales which from the multiplicity of their reflecting surfaces make the whole Animal appear of a perfect Pearl-colour Which by the way may hint us the reason of that so much admired appearance of those so highly esteem'd bodies as also of the like in mother of Pearl-shells and in multitudes of other shelly Sea-substances for they each of them consisting of an infinite number of very thin shells or laminated orbiculations cause such multitudes of reflections that the compositions of them together with the reflections of others that are so thin as to afford colours of which I elsewhere give the reason gives a very pleasant reflection of light And that this is the true cause seems likely first because all those so appearing bodies are compounded of multitudes of plated substances And next that by ordering any trasparent substance after this manner the like Phaenomena may be produc'd this will be made very obvious by the blowing of Glass into exceeding thin shells and then breaking them into scales which any lamp-worker will presently do for a good quantity of these scales laid in a heap together have much the same resemblance of Pearls Another way not less instructive and pleasant is a way which I have several times done which is by working and tossing as 't were a parcel of pure crystalline glass whilst it is kept glowing hot in the blown flame of a Lamp for by that means that purely transparent body will be so divided into an infinite number of plates or small strings with interpos'd aerial plates and fibres that from the multiplicity of the reflections from each of those internal surfaces it may be drawn out into curious Pearl-like or Silver wire which though small will yet be opacous the same thing I have done with a composition of red Colophon and Turpentine and a little Bee's Wax and may be done likewise with Birdlime and such like glutinous and transparent bodies But to return to our description The small blunt head of this Insect was furnish'd on either side of it with a cluster of eyes each of which seem'd to contain but a very few in comparison of what I had observ'd the clusters of other Insects to abound with each of these clusters were beset with a row of small brisles much like the cilia or hairs on the eye-lids and perhaps they serv'd for the same purpose It had two long horns before which were streight and tapering towards the top curiously ring'd or knobb'd and brisled much like the Marsh Weed call'd Horse-tail or Cats-tail having at each knot a fring'd Girdle as I may so call it of smaller hairs and several bigger and larger brisles here and there dispers'd among them besides these it had two shorter horns or feelers which were knotted and fring'd just as the former but wanted brisles and were blunt at the ends the hinder part of the creature was terminated with three tails in every particular resembling the two longer horns that grew out of the head The leggs of it were scal'd and hair'd much like the rest but are not express'd in this Figure the Moth being intangled all in Glew and so the leggs of this appear'd not through the Glass which looked perpendicularly upon the back This Animal probably feeds upon the Paper and covers of Books and perforates in them several small round holes finding perhaps a convenient nourishment in those husks of Hemp and Flax which have pass'd through so many scourings washings dressings and dryings as the parts of old Paper must necessarily have suffer'd the digestive faculty it seems of these little creatures being able yet further to work upon those stubborn parts and reduce them into another form And indeed when I consider what a heap of Saw-dust or chips this little creature which is one of the teeth of Time conveys into its intrals I cannot chuse but remember and admire the excellent contrivance of Nature in placing in Animals such a fire as is continually nourished and supply'd by the materials convey'd into the stomach and fomented by the bellows of the lungs and in so contriving the most admirable fabrick of Animals as to make the very spending and wasting of that fire to be instrumental to the procuring and collecting more materials to augment and cherish it self which indeed seems to be the principal end of all the contrivances observable in bruit Animals Observ. LIII Of a Flea THe strength and beauty of this small creature had it no other relation at all to man would deserve a description For its strength the Microscope is able to make no greater discoveries of it then the naked eye but onely the curious contrivance of its leggs and joints for the exerting that strength is very plainly manifested such as no other creature I have yet observ'd has any thing like it for the joints of it are so adapted that he can as 't were fold them short one within another and suddenly stretch or spring them out to their whole length that is of the fore-leggs the part A of the 34. Scheme lies within B and B within C parallel to or side by side each other but the parts of the two next lie quite contrary that is D without E and E without F but parallel also but the parts of the hinder leggs G H and I bend one within another like the parts of a double jointed Ruler or like the foot legg and thigh of a man these six leggs he clitches up altogether and when he leaps springs them all out and thereby exerts his whole strength at once Schem XXXIV Schem XXXV Observ. LIV. Of a Louse THis is a Creature so officious that 't will be known to every one at one time or other so busie and so impudent that it will be intruding it self in every ones company and so proud and aspiring withall that it fears not to trample on the best and affects nothing so much as a Crown feeds and lives very high and that makes it so saucy as to pull any one by the ears that comes in its way and will never be quiet till it has drawn blood it is troubled at nothing so much as at a man that scratches his head as knowing
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
Now that it is a curve line is manifest by this Experiment I took a Box such as ADGE in the first Figure of the 37. Scheme whose sides ABCD and EFGH were made of two smooth flat plates of Glass then filling it half full with a very strong solution of Salt I filled the other half with very fair fresh water then exposing the opacous side DHGC to the Sun I observ'd both the refraction and inflection of the Sun beams ID KH and marking as exactly as I could the points P N O M by which the Ray KH passed through the compounded medium I found them to be in a curve line for the parts of the medium being continually more dense the neerer they were to the bottom the Ray pf was continually more and more deflected downwards from the streight line Schem XXXVII I could produce many more Examples and Experiments to illustrate and prove this first Proposition viz. that there is such a constitution of some bodies as will cause inflection As not to mention those I have observ'd in Horn Tortoise-shell transparent Gums and resinous Substances The veins of Glass nay of melted Crystal found and much complained of by Glass-grinders and others might sufficiently demonstrate the truth of it to any diligent Observator But that I presume I have by this Example given proof sufficient viz. ocular demonstration to evince that there is such a modulation or bending of the rayes of light as I have call'd inflection differing both from reflection and refraction since they are both made in the superficies this only in the middle and likewise that this is able or sufficient to produce the effects I have ascribed to it It remains therefore to shew that there is such a property in the Air and that it is sufficient to produce all the above mentioned Phaenomena and therefore may be the principal if not the only cause of them First That there is such a property may be proved from this that the parts of the Air are some of them more condens'd others more rarified either by the differing heat or differing pressure it sustains or by the somewhat heterogeneous vapours interspers'd through it For as the Air is more or less rarified so does it more or less refract a ray of light that comes out of a denser medium from the perpendicular This you may find true if you make tryal of this Experiment Take a small Glass-bubble made in the form of that in the second Figure of the 37. Scheme and by heating the Glass very hot and thereby very much rarifying the included Air or which is better by rarifying a small quantity of water included in it into vapours which will expel the most part if not all the Air and then sealing up the small neck of it and letting it cool you may find if you place it in a convenient Instrument that there will be a manifest difference as to the refraction As if in this second Figure you suppose A to represent a small sight or hole through which the eye looks upon an object as C through the Glass-bubble B and the second sight L all which remain exactly fixt in their several places the object C being so cized and placed that it may just seem to touch the upper and under edge of the hole L and so all of it be seen through the small Glass-ball of rarified Air then by breaking off the small seal'd neck of the Bubble without at all stirring the sights object or glass and admitting the external Air you will find your self unable to see the utmost ends of the object but the terminating rayes AE and AD which were before refracted to G and F by the rarified Air will proceed almost directly to I and H which alteration of the rayes seeing there is no other alteration made in the Organ by which the Experiment is tryed save only the admission or exclusion of the condens'd Air must necessarily be caused by the variation of the medium contain'd in the Glass B the greatest difficulty in the making of which Experiment is from the uneven surfaces of the bubble which will represent an uneven image of the object Now that there is such a difference of the upper and under parts of the Air is clear enough evinc'd from the late improvement of the Torricellian Experiment which has been tryed at the tops and feet of Mountains and may be further illustrated and inquired into by a means which some whiles since I thought of and us'd for the finding by what degrees the Air passes from such a degree of Density to such a degree of Rarity And another for the finding what pressure was requisite to make it pass from such a degree of Rarefaction to a determinate Density Which Experiments because they may be useful to illustrate the present Inquiry I shall briefly describe I took then a small Glass-pipe AB about the bigness of a Swans quill and about four foot long which was very equally drawn so that as far as I could perceive no one part was bigger then another This Tube being open at both ends I fitted into another small Tube DE that had a small bore just big enough to contain the small Pipe and this was seal'd up at one and open at the other end about which open end I fastned a small wooden box C with cement so that filling the bigger Tube and part of the box with Quicksilver I could thrust the smaller Tube into it till it well all covered with the Quicksilver Having thus done I fastned my bigger Tube against the side of a wall that it might stand the steadier and plunging the small Tube cleer under the Mercury in the box I stopt the upper end of it very fast with cement then lifting up the small Tube I drew it up by a small pully and a string that I had fastned to the top of the Room and found the height of the Mercurial Cylinder to be about twenty nine inches Then letting down the Tube again I opened the top and then thrust down the small Tube till I perceived the Quicksilver to rise within it to a mark that I had plac'd just an inch from the top and immediately clapping on a small peice of cement that I had kept warm I with a hot Iron seal'd up the top very fast then letting it cool that both the cement might grow hard and more especially that the Air might come to its temper natural for the Day I try'd the Experiment in I observ'd diligently and found the included Air to be exactly an Inch. Here you are to take notice that after the Air is seal'd up the top of the Tube is not to be elevated above the superficies of the Quicksilver in the box till the surface of that within the Tube be equal to it for the Quicksilver as I have elsewhere prov'd being more heterogeneous to the Glass then the Air will not naturally rise up so high within the small Pipe
of it are too large to be comprehended and some too little to be perceived And from thence it must follow that not having a full sensation of the Object we must be very lame and imperfect in our conceptions about it and in all the propositions which we build upon it hence we often take the shadow of things for the substance small appearances for good similitudes similitudes for definitions and even many of those which we think to be the most solid definitions are rather expressions of our own misguided apprehensions then of the true nature of the things themselves The effects of these imperfections are manifested in different ways according to the temper and disposition of the several minds of men some they incline to gross ignorance and stupidity and others to a presumptuous imposing on other mens Opinions and a confident dogmatizing on matters whereof there is no assurance to be given Thus all the uncertainty and mistakes of humane actions proceed either from the narrowness and wandring of our Senses from the slipperiness or delusion of our Memory from the confinement or rashness of our Understanding so that 't is no wonder that our power over natural causes and effects is so slowly improvâ—d seeing we are not only to contend with the obscurity and difficulty of the things whereon we work and think but even the forces of our own minds conspire to betray us These being the dangers in the process of humane Reason the remedies of them all can only proceed from the real the mechanical the experimental Philosophy which has this advantage over the Philosophy of discourse and disputation that whereas that chiefly aims at the subtilty of its Deductions and Conclusions without much regard to the first ground-work which ought to be well laid on the Sense and Memory so this intends the right ordering of them all and the making them serviceable to each other The first thing to be undertaken in this weighty work is a watchfulness over the failings and an inlargement of the dominion of the Senses To which end it is requisite first That there should be a scrupulous choice and a strict examination of the reality constancy and certainty of the Particulars that we admit This is the first rise whereon truth is to begin and here the most severe and most impartial diligence must be imployed the storing up of all without any regard to evidence or use will only tend to darkness and confusion We must not therefore esteem the riches of our Philosophical treasure by the number only but chiefly by the weight the most vulgar Instances are not to be neglected but above all the most instructive are to be entertain'd the footsteps of Nature are to be trac'd not only in her ordinary course but when she seems to be put to her shifts to make many doublings and turnings and to use some kind of art in indeavouring to avoid our discovery The next care to be taken in respect of the Senses is a supplying of their infirmities with Instruments and as it were the adding of artificial Organs to the natural this in one of them has been of late years accomplisht with prodigious benefit to all sorts of useful knowledge by the invention of Optical Glasses By the means of Telescopes there is nothing so far distant but may be represented to our view and by the help of Microscopes there is nothing so small as to escape our inquiry hence there is a new visible World discovered to the understanding By this means the Heavens are open'd and a vast number of new Stars and new Motions and new Productions appear in them to which all the antient Astronomers were utterly Strangers By this the Earth it self which lyes so neer us under our feet shews quite a new thing to us and in every little particle of its matter we now behold almost as great a variety of Creatures as we were able before to reckon up in the whole Universe it self It seems not improbable but that by these helps the subtilty of the composition of Bodies the structure of their parts the various texture of their matter the instruments and manner of their inward motions and all the other possible appearances of things may come to be more fully discovered all which the antient Peripateticks were content to comprehend in two general and unless further explain'd useless words of Matter and Form From whence there may arise many admirable advantages towards the increase of the Operative and the Mechanick Knowledge to which this Age seems so much inclined because we may perhaps be inabled to discern all the secret workings of Nature almost in the same manner as we do those that are the productions of Art and are manag'd by Wheels and Engines and Springs that were devised by humane Wit In this kind I here present to the World my imperfect Indeavours which though they shall prove no other way considerable yet I hope they may be in some measure useful to the main Design of a reformation in Philosophy if it be only by shewing that there is not so much requir'd towards it any strength of Imagination or exactness of Method or depth of Contemplation though the addition of these where they can be had must needs produce a much more perfect composure as a sincere Hand and a faithful Eye to examine and to record the things themselves as they appear And I beg my Reader to let me take the boldness to assure him that in this present condition of knowledge a man so qualified as I have indeavoured to be only with resolution and integrity and plain intentions of imploying his Senses aright may venture to compare the reality and the usefulness of his services towards the true Philosophy with those of other men that are of much stronger and more acute speculations that shall not make use of the same method by the Senses The truth is the Science of Nature has been already too long made only a work of the Brain and the Fancy It is now high time that it should return to the plainness and soundness of Observations on material and obvious things It is said of great Empires That the best way to preserve them from decay is to bring them back to the first Principles and Arts on which they did begin The same is undoubtedly true in Philosophy that by wandring far away into invisible Notions has almost quite destroy'd it self and it can never be recovered or continued but by returning into the same sensible paths in which it did at first proceed If therefore the Reader expects from me any infallible Deductions or certainty of Axioms I am to say for my self that those stronger Works of Wit and Imagination are above my weak Abilities or if they had not been so I would not have made use of them in this present Subject before me Whereever he finds that I have ventur'd at any small Conjectures at the causes of the things that I have observed
I beseech him to look upon them only as doubtful Problems and uncertain ghesses and not as unquestionable Conclusions or matters of unconfutable Science I have produced nothing here with intent to bind his understanding to an implicit consent I am so far from that that I desire him not absolutely to rely upon these Observations of my eyes if he finds them contradicted by the future Ocular Experiments of sober and impartial Discoverers As for my part I have obtained my end if these my small Labours shall be thought fit to take up some place in the large stock of natural Observations which so many hands are busie in providing If I have contributed the meanest foundations whereon others may raise nobler Superstructures I am abundantly satisfied and all my ambition is that I may serve to the great Philosophers of this Age as the makers and the grinders of my Glasses did to me that I may prepare and furnish them with some Materials which they may afterwards order and manage with better skill and to far greater advantage The next remedies in this universal cure of the Mind are to be applyed to the Memory and they are to consist of such Directions as may inform us what things are best to be stor'd up for our purpose and which is the best way of so disposing them that they may not only be kept in safety but ready and convenient to be at any time produc'd for use as occasion shall require But I will not here prevent my self in what I may say in another Discourse wherein I shall make an attempt to propose some Considerations of the manner of compiling a Natural and Artificial History and of so ranging and registring its Particulars into Philosophical Tables as may make them most useful for the raising of Axioms and Theories The last indeed is the most hazardous Enterprize and yet the most necessary and that is to take such care that the Judgment and the Reason of Man which is the third Faculty to be repair'd and improv'd should receive such assistance as to avoid the dangers to which it is by nature most subject The Imperfections which I have already mention'd to which it is lyable do either belong to the extent or the goodness of its knowledge and here the difficulty is the greater least that which may be thought a remedy for the one should prove destructive to the other least by seeking to inlarge our Knowledge we should render it weak and uncertain and least by being too scrupulous and exact about every Circumstance of it we should confine and streighten it too much In both these the middle wayes are to be taken nothing is to be omitted and yet every thing to pass a mature deliberation No Intelligence from Men of all Professions and quarters of the World to be slighted and yet all to be so severely examin'd that there remain no room for doubt or instability much rigour in admitting much strictness in comparing and above all much slowness in debating and shyness in determining is to be practised The Understanding is to order all the inferiour services of the lower Faculties but yet it is to do this only as a lawful Master and not as a Tyrant It must not incroach upon their Offices nor take upon it self the employments which belong to either of them It must watch the irregularities of the Senses but it must not go before them or prevent their information It must examine range and dispose of the bank which is laid up in the Memory but it must be sure to make distinction between the sober and well collected heap and the extravagant Idea's and mistaken Images which there it may sometimes light upon So many are the links upon which the true Philosophy depends of which if anyone be loose or weak the whole chain is in danger of being dissolv'd it is to begin with the Hands and Eyes and to proceed on through the Memory to be continued by the Reason nor is it to stop there but to come about to the Hands and Eyes again and so by a continual passage round from one Faculty to another it is to be maintained in life and strength as much as the body of man is by the circulation of the blood through the several parts of the body the Arms the Fat the Lungs the Heart and the Head If once this method were followed with diligence and attention there is nothing that lyes within the power of human Wit or which is far more effectual of human Industry which we might not compass we might not only hope for Inventions to equalize those of Copernicus Galileo Gilbert Harvy and of others whose Names are almost lost that were the Inventor's of Gun-powder the Seamans Compass Printing Etching Graving Microscopes c. but multitudes that may far exceed them for even those discoveries seem to have been the products of some such method though but imperfect What may not be therefore expected from it if thoroughly prosecuted Talking and contention of Arguments would soon be turn'd into labours all the fine dreams of Opinions and universal metaphysical natures which the luxury of subtil Brains has devis'd would quickly vanish and give place to solid Histories Experiments and Works And as at first mankind fell by tasting of the forbidden Tree of Knowledge so we their Posterity may be in part restor'd by the same way not only by beholding and contemplating but by tasting too those fruits of Natural knowledge that were never yet forbidden From hence the World may be assisted with variety of Inventions new matter for Sciences may be collected the old improv'd and their rust rubb'd away and as it is by the benefit of Senses that we receive all our Skill in the works of Nature so they also may be wonderfully benefited by it and may be guided to an easier and more exact performance of their Offices 't is not unlikely but that we may find out wherein our Senses are deficient and as easily find wayes of repairing them The Indeavours of Skilful men have been most conversant about the assistance of the Eye and many noble Productions have followed upon it and from hence we may conclude that there is a way open'd for advancing the operations not only of all other Senses but even of the Eye it self that which has been already done ought not to content us but rather to incourage us to proceed further and to attempt greater things in the same and different wayes 'T is not unlikely but that there may be yet invented several other helps for the eye as much exceeding those already found as those do the bare eye such as by which we may perhaps be able to discover living Creatures in the Moon or other Planets the figures of the compounding Particles of matter and the particular Schematisms and Textures of Bodies And as Glasses have highly promoted our seeing so 't is not improbable but that there may be found many Mechanical Inventions to