the same Weight yet they are nothing near of the same Bulk the Bubble by reason of its capacious Cavity which contains nothing but Air or something that weighs less than Air being perhaps a hundred or two hundred times bigger than the Metalline Counterpoise 2dly That according to an Hydrostatical Law which you know I have lately had occasion to make out if two Bodies of equal Gravity but unequal Bulk were to be weighed in another Medium they will be no longer equiponderant but if the new Medium be heavier the greater Body as being lighter in specie will lose more of its Weight than the lesser and more compact but if the new Medium be lighter than the first then the bigger Body will outweigh the lesser And this Disparity arising from the Change of Mediums will be so much the greater by how much the greater Inequality of Bulk there is between the Bodies formerly equiponderant 3dly That laying these two together I consider'd that 't would be all one as to the Effect to be produced wherein the Bodies were weighed in Mediums of differing Gravity or in the same Medium in case its specifick Gravity were considerably altered And consequently that since it appeared by the Baroscope that the Weight of the Air was sometimes heavier and sometimes lighter the Alteration of it in Point of Gravity from the Weight it was of at first counterpoising of the Bubble in it would unequally affect so large and hollow a Body as the Bubble and so small and dense an one as a Metalline Weight and when the Air by an Encrease of Gravity should become a heavier Medium than before it would buoy up the Glass more than the Counterpoize and if it grew lighter than it was at first would suffer the former to proponderate The Illustration and Proof can scarce be added in few Words but if it be desired I may God permitting send you them at my next leisure And though our English Air being about a thousand times lighter than Water the Difference in Weight of so little Air as is but equal in Bulk to a Bubble seem'd to give small Hopes that it would be sensible upon a Ballance yet by making the Bubble very large and light I supposed and found the Event I have already related 2. The hermetically seal'd glass Bubble I imployed was of the Bigness of a somewhat large Orange and weighed about one Drachm and ten Grains I thought it very possible if I had been better furnished with Conveniences wherein I afterwards found I was not mistaken to make among many that might be expected to miscarry some that might be preferrable to this either for Capacity or Lightness or both especially if Care be taken that they be not seal'd up whilst they are too hot For though one would think that it were advantageous to ratify and drive out the Air as much as is possible because in such seal'd Bubbles the Air it self as I have elsewhere shewn has a Weight yet the Advantage countervails not the Inconvenience of being obliged to increase the Weight of the Glass which when it includes highly ratified Air if it be not somewhat strong will be broken by the Pressure of the external Air as I have sufficiently tried 3. By reason of the Difficulties and Casualties that may happen about the procuring and preparing such large and light Bubbles as I have been lately mentioning it may in some Cases prove a Convenience to be informed that I have sometimes instead of one sufficiently large Bubble made Use of two that were smaller And though a single Bubble of competent Bigness be much preferrable by reason that a far less Quantity and Weight of Glass is requisite to comprize an equal Capacity when the Glass is blown into a single Bubble than when it is divided into two yet I found that the employing of two instead of one did not so ill answer my Expectation but that they may for a need serve the turn instead of the other than which they are much easier to be procured This Instrument may be much improved by divers Accommodations As 1st there may be fitted to the Ansa or Checks of the Ballance an Arch of a Circle divided into 15 or 20 Degrees more or less according to the Goodness of the Ballance that the Tongue resting over against any of these Divisions may readily and without Calculation shew the Quantity of the Angle by which when the Scales propend either way the Tongue declines from the Perpendicular and the Beam from its Horizontal Parallelism 2dly Those that will be so curious may instead of the ordinary Counterpoise of Brass imploy one of Gold or at least of Lead whereof the latter being of equal Weight with Brass is much less in Bulk and the former amounts not to half its Bigness 3dly These Parts of the Ballance that may be made of Copper or Brass without any Prejudice to the Exactness will by being made of one of those Metals be less subject than Steel to rust with long standing 4thly Instead of the Scales the Bubble may be hung at one End of the Beam and only a Counterpoise to it at the other that the Beam may not be burden'd with unnecessary Weight 5thly The whole Instrument if placed in a small Frame like a square Lanthorn with Glass Windows and a Hole at the top for the Commerce of the internal and external Air will be more free from Dust and irregular Agitations to the latter of which it will otherwise be sometimes liable 6thly This Instrument being accommodated with a light Wheel and an Index may be made to show much more minute Variations than otherwise 7thly The Length of the Beam and Exquisitness of the Ballance may easily without any of the foregoing Helps and much more with them make the Instrument far exacter than those I was reduced to imploy And to these Accommodations divers other may be suggested by a further Consideration of the Nature of the thing Though in some Respects the Statical Baroscope be inferiour to the Mercurial yet in others it has its own Advantages and Conveniency about it At first it confirms ad oculum our former Doctrine that the falling and rising of the Mercury depended upon the varying Weight of the Atmosphere since in this Baroscope it cannot be pretended that a fuga vacui or a Funiculus is the Cause of the Changes we observe 2dly It shows that not only the Air has Weight but a more considerable one than some learned Men who will allow me to have proved that it has some Weight will admit 3dly This Statical Baroscope will oftentimes be more parable than the other for many will find it more easy to procure a good pair of Gold Scales and a Bubble or two than a long Cane seal'd a Quantity of Mercury and all the other Requisites of the Mercurial Baroscope especially if we comprize the Trouble and Skill that is requisite to free the deserted part of the Tube from
Air. 4thly And whereas the Difficulty of removing the Mercurial Instrument has kept Men from so much as attempting to do it even to Neighbouring Places the essential Parts of the Scale Baroscope for the Frame is none of them may very easily in a little room be carried wheresoever one will without the Hazard of being spoil'd or injur'd 5thly There is not in Statical Baroscopes as in the other a Danger of Uncertainty as to the Goodness of the Instrument by reason that in the Mercurial the Air is in some more and in some less perfectly excluded whereas in these that Consideration has no Place 6thly It being as I formerly intimated very possible to discover Hydrostatically both the Bigness of the Bubble and the Contents of the Cavity and the Weight and Dimensions of the glassy Substance which together with the included Air make up the Bubble much may be discovered by this Instrument as to the Weight of the Air absolute or respective For when the Mercury in the Mercurial Baroscope is either very high or very low or at a middle Station between its greatest and least Height bringing the Scale-Baroscope to an exact Equilibrium with very minute Divisions of a Grain you may by watchfully observing when the Mercury is risen or fallen just an Inch or a 4th or ◠of an Inch. c. and putting in the like minute Divisions of a Grain to the lighter Scale till you have again brought the Ballance to an Equilibrium you may I say determine what known Weight in the Statical Baroscope answers such determinate Altitudes of the ascending and descending Mercury in the Mercurial And if your Ballance be accommodated with a divided Arch or a Whele and Index these Observations will assist you for the future to determine by seeing the Inclination of the Tongue or the Degree mark'd by the Index to conclude readily what Potency the Bubble has by the Change of the Atmosphere's Weight acquired or lost Some Observations of this Nature I watchfully made sometimes putting in a 64th sometimes a 32d sometimes a 16th and sometimes heavier parts of a Grain to the lighter Scale But one that knew not for what Uses these little Papers were coming to a Window where my Baroscope stood so unluckily shook them out of the Scales and confounded them that he robb'd me of the Opportunity of making the nice Observations I intended though I had the Satisfaction of seeing that they were to be made 7thly By this Statical Instrument we may be assisted to compare the Mercurial Baroscopes of several Places though never so distant and to make some Estimates of the Gravities of the Air therein As if for instance I have found by Observation that the Bubble I imploy and one may have made divers Bubbles of several Sizes that the one may repair any Mischance that may happen to another weighed just a Drachm when the Mercurial Cylinder was at the Height of 29½ Inches which in some Places I have found a moderate Altitude and that the Addition of the 16th part of a Grain is requisite to keep the Bubble in an Equilibrium when the Mercury is risen an 8th or any determinate part of an Inch above the former Station When I come to another Place where there is a Mercurial Barometer as well freed from Air as mine for that must be supposed if taking out my Scale-Instrument it appears to weigh precisely a Drachm and the Mercury in the Baroscope there stand at 29½ Inches we may conclude the Gravity of the Atmosphere not to be sensibly unequal in both those two Places though very distant And though there be no Baroscope there yet if there be an additional Weight as for instance the 16th part of a Grain requisite to be added to the Bubble to bring the Scales to an Equilibrium it will appear that the Air at this second Place is at that time so much heavier than the Air of the former Place was when the Mercury stood at 29½ Inches But in making such Comparisons we must not forget to consider the Situation of the several Places if we mean to make Estimates not only of the Weight of the Atmosphere but of the Weight and Density of the Air. For though the Scales will show as hath been said whether there be a Difference of Weight in the Atmosphere at the two Places yet if one of them be in a Vale or Bottom and the other on the Top or some elevated part of a Hill it is not to be expected that the Atmosphere in this latter Place should gravitate as much as the Atmosphere in the former on which a longer Pillar of Air does lean or weigh so that the Bubble in both these Places should be precisely of the same Weight And the mention I have made of the differing Situation of Places puts me in mind of something that may prove another Use of our Statical Baroscope and which I had Thoughts of making Trial of but was accidentally hindered from the Opportunity of doing it namely that by exactly poizing the Bubble at the Foot of a high Steeple or Hill and carrying it in its close Frame to the top one may by the Weight requisite to be added to the Counterpoize there to bring the Beam to its horizontal Position observe the Difference of the Weight of the Air at the bottom and at the top and in case the Hill be high enough at some intermediate Stations But how this may assist Men to estimate the absolute or comparative Height of Mountains and other elevated Places and what other Uses the Instrument may be put to when it is duly improved and the Cautions that may be requisite in the several Cases which shall be proposed I must leave to more leisure and further Consideration I caused to be made with great Care by a skilful Mathematical-Instrument-maker a hollow Cube of Brass whose every Side was as exactly as could be procured an English Inch. This we carefully counterpoised in a very good pair of Scales and found it to weigh 11 Drachms 1 Grain and ½ Troy-Weight Then placing it in one of the Scales as horizontally as we were able we warily fill'd it with clear common Water of the best sort of that called pump-Pump-water till the Surface of the Water seem'd to lie as level as we could make it to the Brims of the Vessel then weighing it carefully we found the Water alone for the Cube had been counterpoized before to weigh 254 9 16 Grains So that in regard 't is scarce possible to know that such a Vessel is so filled as to come nearer Exactness than within a Drop or two I presume we may without any sensible Error suppose an Inch of Water to weigh 256 Grains which latter Number I rather chufe because its aliquot Parts make it more convenient and it agrees well enough with some Trials that I made with solid Cubes to measure the true Weight of a Cubick Inch of Water This done the Vessel was
well dried within and the same Scales being well counterpoized the Instrument was so too and being placed on one of the Scales as Horizontically as we could Mercury distilled to have it more pure was warily put into it till by Degrees it had filled the Vessel as to Sight but we neither expected nor found that it would be brought to an exact Level and exquisitly fill all the Corners of the Vessel But when it seem'd to be so well filled that even a critical Eye could not readily find fault with it though the Mercury appeared capable of some Accession without overflowing we weighed the Quicksilver it self for the Vessel had been counterpoized before and found it to weigh 7 Ounces 2 Drachms Troy which falling somewhat short though not very much of what the above-mention'd Weight of the Water required we tried to add a little more Quicksilver without making it run over and found the Increase of 82 Grains so that now the Quicksilver weighed 7 Ounces 3 Drachms 22 Grains but it seem'd when the Eye was placed in a Level with the Brims of the Vessel that it was rather a little of the highest than any way depressed and yet was not so full but that we could add 112 Grains to the former Weight without making it run over and perhaps we might have added yet more but I decline doing it because the last mentioned Accession seem'd manifestly to make it so much swell above the Brims of the Vessel By all which 't is evident that 't is scarce possible to determine precisely by such hollow Instruments the true Weight of a Cubick Inch of Quick-silver And therefore since by other ways of Trial I have found the Proportion of the Weight of Mercury to Water of the same Bulk to be somewhat less than that of 14 to 1 I think we may without any considerable Inconvenience suppose the Weight of a Cubick Inch of Quick-silver to be 3580 Grains which is near 14 times the above-mentioned Weight of a Cubick Inch of Water and comes near enough to the second or middlemost of the three Estimates lately set down and by the least Estimate of all it appears that a Cubick Inch of Quicksilver weighs 7¼ Ounces Troy Weight that is 8 Ounces Averdupois Weight And consequently when the Quicksilver of the Baroscope kept up by the Counterpoize of the Air 30 Inches as I have observed it several times to be within a Month last past the Weight of the Air that is incumbent on an Inch Square here below amounts to 18 l. ⅛ Troy Weight that is in Averdupois Weight 15 l. 1 17. As 11 to 14 or rather as 355 to 452 so is the Area of a Square inscribed in a Circle to the Area of the circumscribed Circle Hence 355 452 1 1 2732394. Hence if the side of an inscribed Square be an Inch that multiplied by an Inch renders a Cubick Inch for the solid Content In like manner if the Height of a Cylinder erected on the circumscribing Circle be an Inch the solid Content of that Cylinder is 1,2732394 Wherefore 1 and 1 2732394 multiplied by the Weight of the Cubick Inch of any kind of Metal give the Weight of a Cubick Inch and of a Cylindrick Inch that circumscribes the same whence an Inch Table for both is easily made by continual Addition or for any Height propounded multiplying both by the same Mr. Townly's Register if I misremember not Nov. 23 2    28. 98 24 8    29. 54  9 p   28. 90 25 3¼     80 27 9 p    99 29 9    28. 97  9 p   29. 09 Dec. 6 9 p   28. 97 7 9     60 8 9    29. 05 11 9    28. 93  3 p   29. 01 13 8◠   28. 90  9 p    95 25 9 p   29. 04 26 9 p   28. 32 28 10 p   29. 13 Jan. 1 9 p   28. 99 2 9     82 3 9    29. 08  9 p    06 5 10    28. 70 6 10    29. 09  9½ p   28. 62 7 8    28. 99 12 10    28. 88  4 p    98 16 1    29. 13  9 p   28. 65 17 10     14 21 9½    29. 05 22 4    28. 99  9 p    94 23 9     99 24 11 p   29. 06 25 9    28. 50  9 p   29. 10  29 9   28. 90   9 p   71  30 8    80 31 9 p 30. 12   Febr. 1 12   22   2 8½  29. 97   15 9 p   28. 99 16 9 p    95 17 8    29. 10 Mar. 2 9 p   28. 98 4 8½     78  9     86 12 9    28. 80  9 p    66 13 8½    29. 03 1671 Apr. 1 6 p   28. 99  2 9 p   78 3 8½    29. 03 June 8 1    29. 18  8 p   28. 86 9 7     99 Aug. 12 6   28. 90 Sept. 6 8½    29. 15 7 10½    28. 65 8 7½    29. 05 12 9½    28. 98 29 8    28. 96  3 p   29. 08 30 9 p   29. 19 Octo. 1 10   28. 63  3 8   29. 10 A Register kept by Mr. Locke in Oxford d h Th. Bar. Wind. Weather at Oxford 1666 June 24 9 70 29  N E 2 Fair.  22 76 ․ 29 1   Fair. 25 4˙ 73˙ 29 1˙ N E 1 Fair.  10 74 ․ 29 1˙ E 1 Fair.  15 ․ 77 ․ 29 1 ․ S E 2 Fair. 26 9˙ 73˙ 28 8 ․ N 1 Fair.  12 75 ․ 28 7˙ N E 1 Thunder  13 75 ․ 28 7˙ S W 4 Thunder Rain Hail  14 74 ․ 28 8 ․ N 0 Thunder Rain  18 73 ․ 28 8 ․ N 1 Clouds dry  22 72 ․ 28 8 ․   Fair. 27 7 70 ․ 28 8 ․ N W 1 Rain  9 70 ․ 28 8 ․ N W 1 Rain  16 68˙ 28 8 ․ W 1 Fair. 28 9 63˙ 29 1˙ W 0 Clouds  17 67˙ 29 1˙ N 1 Clouds 29 9 63˙ 29 2 ․ N 1 Clouds  19 69 ․ 29 1˙ N 1 Clouds 30 9 64 ․ 29 2 ․
some of the Titles though I left the others to those that had made Experiments or Observations about them Next That having through the Fraud or Negligence of some Persons lost sundry loose Papers that I had provided for the History of the Air my Unwillingness that the rest should undergo the same Fate invited me to impart them to many as the best Expedient to secure them To which I Thirdly add an Inducement which though last named was the first in Efficacy as that which made the other two significant namely that I had more than once observed that when a Work of this Nature has been once begun and taken notice of in such an inquisitive and active Age as this of ours it seldom fails to excite the Curiosity and Industry of others whom if the Design be any thing well laid the Utility that it promises will invite to carry it on TITLE I. What we understand by the AIR BY the Air I commonly understand that thin fluid diaphanous compressible and dilatable Body in which we breath and wherein we move which envelops the Earth on all sides to a great height above the highest Mountains but yet is so different from the Aether or Vacuum in the intermundane or interplanetary Spaces that it refracts the Rays of the Moon and other remoter Luminaries TITLE II. Of the constant and permanent Ingredients of the Air. A short Answer to a Question about the Nature of the Air given by Mr. Boyle to Mr. H. Oldenburg AS to your Question What I think the Air to be I shall in the first place take it for granted that by the Air you mean not either the pure Element of Air which some nor that Etherial or Celestial Substance that others upon what Grounds I must not here examine assert but that which I am wont to call the Atmospherical Air which is that common Air we breath and move in But though I know you too well to suspect that you design any Ambiguity in your Question yet I shall not adventure to answer it till I have premised a Distinction that is not usual For according to my Thoughts the Air may be taken either for that which is Temporary if I may so call it or in a Transient State or that which is Lasting and in a Permanent State This Distinction which perhaps you look'd not for I shall illustrate by this Example That if you sufficiently heat an Eolipile furnished with Water and stay a pretty while to afford time for the expulsion of the Aerial Particles by the Aqueous Vapours you may afterwards observe that these last named will be driven out in multitudes and with a noise and will emulate a Wind or Stream of Air by blowing Coals held at a convenient distance like a pair of Bellows and by producing a sharp and whistling Sound against the edg of a Knife held in a convenient Posture almost upon the Orifice of the Pipe whence they issue out But this vapid Stream though in these and some other things it imitates true Air whilst the vehement Agitation lasts which the Vapours it consists of received from the Fire yet in a very short time especially if the Weather or the Vessels it enters into be cold loses the temporary Form it seemed to have of Air and returns to Water as it was at first This premised I come to speak directly but dare not do it confidently to your Question For though possibly I may have made as many Trials as another about the Nature of the Air yet I freely confess to you that I much suspect there lies yet something concealed in it that needs a further Discovery which may perhaps be made by further Trials But in the mean time not wholly to baffle your Curiosity since 't is so modest as to desire to know of me not what the true Nature of the Air is but what I guess concerning its chiefest Property or Attribute I will acquaint you with some of the Thoughts I long ago had and which I yet took upon my self and desire to have them look'd upon by you but as Conjectures entertain'd only till farther Discoveries confirm them or suggest better in their room It seems then not improbable to me that our Atmospherical Air may consist of three differing Kinds of Corpuscles The first is made of that numberless Multitude and great Variety of Particles which under the form of Vapours or dry Exhalations ascend from the Earth Water Minerals Vegetables and Animals c. and in a word of whatever Substances are elevated by the Celestial or Subterraneal Heats and made to diffuse themselves into the Atmosphere The second sort of Particles that make the Air may be yet more subtile than the former and consist of such exceeding minute Parts as make up the Magnetical Steams of our Terrestrial Globe and the innumerable Particles that the Sun and other Stars that seem to shine of themselves do either emit out of their own Bodies or by their Pressure thrust against our Eyes and thereby produce what we call Light which whether we explicate it by the Epicurean or Cartesian Hypothesis argues a great Plenty of a Celestial or some other very subtile Matter to be dispersed through or harboured in the Intervals of the stabler or grosser Corpuscles of the Atmosphere But because you expect from me a distinguishing and as it were Characteristick Quality which may put a difference between the Parts already named of the Atmosphere and those to which most of the Phenomena of our Engine and many other Pneumatical Experiments seem to be due I shall add a third sort of Atmospherical Particles compared with which I have not yet found any whereto the Name of Air does so deservedly belong And this sort of Particles are those which are not only for a while by manifest outward Agents made Elastical but are permanently so and on that account may be stil'd Perennial Air. Of the Structure of the Elastical Particles of the Air divers Conceptions may be framed according to the several Contrivances Men may devise to answer the Phenomena For one may think them to be like the Springs of Watches coil'd up and still endeavouring to fly abroad One may also fancy a Portion of Air to be like a Lock or Parcel of curled Hairs of Wooll which being compressed by an external Force or their own Weight may have a continual endeavour to stretch themselves out and thrust away the neighbouring Particles and whatever other Bodies would hinder them to recover their former State or attain their full Liberty One may also fancy them like extreamly slender Wires such as those of Gold and Silver that Tradesmen unwind from some Cylindrical Bodies of differing Sizes on which they were rolled which Pieces of Spiral or curled Wire may be as of differing Substances and Consistences so of very differing Lengths and Thicknesses and have their Curls greater or lesser nearer each other or more distant and be otherwise diversified and yet all have
hastula H. K. perforata sit continuo ductu usque ad emboli K. S. fundum pateat aeri ingredienti via H. S. sed foramini S. adjecta sit valvula quae aeri regressum obstruat Similiter modioli fundo in I. valvula exteriùs apposita aperiatur ingesto aeri transitum praebens sed aeri intra vas compresso cum nusquam exitus pateat valvula ipsa modioli foramen I. occludit Hastulae verò H. K. exterior facies sit in helicem striata lamellae M. N. tanquam matrici congruat quae in M. N. cochleolis adnecti queat exteriùs vasi quasi esset ansae fulcrum Ubi immissum fuerit quantum satis est aquae cochleolis M. N. revolutis disjungatur matrix à vase tum attractâ ansâ H. O. unà cum lamellâ M. N. attrahitur embolus K. S. per apertum ductum H. S. ingreditur aer modiolum implens Impulso deinde embolo valvula ad S. clauditur aer ex modiolo per patentem valvulam I. ingeritur in vas ex quo nequit exire neque aquam propellere clauso scilicet epistomio E. foramine A. qua propter comprimitur densatur ideoque attracto denuo embolo K. S. inclusus vasi aer se latius explicare connitens valvulam I. valide applicat foramini modioli sibique exitum obstruit Toties adducitur atque reducitur embolus aer ingeritur quoad magna premendi difficultas percipiatur ubi eò ventum fuerit tunc lamella M. N. iterum vasi adnectatur suis cochleolis nec jam embolus rectâ adduci potest sed areptum in O. manubrium versatur embolus intrà modiolum circumactus sensim attollitur qui deinde revoluto in contrarium manubrio deprimitur multâ vi aer in vase comprimitur Laxato demum Epistomio E. compressus in vase aer aquam exprimit per tubum C. D. primùm quidem vehementius subinde remissius prout aeris vis elastica sensim longuescit Hoc idem quod de aere intra vas comprimendo ad aquam evibrandam comminisci placuit servatâ analogiâ dicendum est de aere tum conatu manûs rectâ trusillum impellentis tum ope cochleae similiter conformatae intrà conceptaculum comprimendo ut ex fistulâ deinde multâ vi emittatur plumbea glans ubi reseratus aeri exitus illum subitò dilatari permiserit Quin pneumatica hujusmodi tormenta citrà conceptaculum aeris compressi construere non inutilè accidat si quemadmodum nostrates pueri surculos sambuceos fungosâ medullâ exhauriunt utraque tubuli extremitate papyraceis globulis obstructâ alterum globulum congruo cylindro propellunt atque inclufum aerem densant quoad aeris vim elasticam impellentis manus conatum non ferens extremus alter globulus edito seloppo expellatur ita ferream fistulam longiorem paraveris cujus alteri extremitati immittatur plumbea glans obducta papyro aut simili materiâ ut exquisitè tubi osculum implens demum universam aeris vim excipiar alteram extremitatem aliquot spiris ambiat cava cochlea quam impleat cylindrus ferreus in congruentem cochleam deformatus si enim hujusmodi cylindrus vix brevior fuerit quà m fistula apto manubrio convolutus in fistulam sensim immittatur totum aerem quo fistula replebatur ad exiguas spatii angustias adiget ex quibus magnâ vi demum quâ data porta erumpens ejaculabitur plumbeum globulum TITLE V. Of the Magnetical Particles in the Air.  TITLE VI. Of the Destruction Generation Absorption and Extrication of the Air. New Experiments about producing of Air. And examining the Bodies produced THAT the Air has a great Interest in the Production of many Phenomena of Nature either not formerly known or not formerly ascribed unto it as the chief Agent if as any at all has been I suppose sufficiently manifested by our own Experiments as well as by those published by abler Writers That also the Air is necessary not only to the well-being but to the verry Being and Motions of the Generality of Animals will be easily deduc'd from those Trials whereby we have made it appear that Animals whose Blood is hot may be killed in our Engine by the withdrawing of the Air in about one Minute of an Hour and that even those minute Creatures whose Blood or Analogous Juice is cold will for the most part without excepting Cheese-Mites themselves presently lose all their visible Motions upon the Recess of the Air may appear from our Experiments about Respiration Wherefore the Air being a Body so important in our Speculations of Nature and so necessary to the Continuance of our Lives I could not but think it deserv'd that we should solicitously inquire whether it may or may not be produc'd by Art for if it can be so by any not very uneasily practicable ways the Discovery may not only help us to explicate some difficult Phenomena of Nature but may afford us among several other Uses that of enabling us to supply divers if not also submarine Navigators with fresh Air produced under Water and thereby lengthen their staying in Places where the Continuance of it may be of great Use both speculative and practical Upon these and the like Motives I resolv'd notwithstanding the Difficulties I foresaw my Curiosity would meet with in so new an Attempt to try what I could do But before I relate the Success of this Attempt I must premise a couple of necessary Advertisements And first when I here speak of Production of Air I desire to be understood in a familiar Sense meaning by that Expression the obtaining a sensible Quantity of Air from Bodies wherein it did not appear before they were handled after our way that so much Air if any at all was pre-existent This I say because I would not in this Place needlesly ingage in the Controversy about the Ingenerability as they speak or the mutual Transmutation of the Bodies that are called Elementary for though I am not sure but that some of our Experiments may argue a new and real Production of Air or a Generation of it in the stricter Sense yet I shall now imploy the words Generation and Production in the large and popular Acception and would signify by them as I lately intimated the obtaining of a sensible Quantity of Aerial Substances from Bodies that did not appear to have it whether this obtain'd Substance were due to an Extrication and Union of Aerial Particles latent in the Pores of the Bodies that afforded it or to a real Production or Generation of Air no where existent antecedently to our Experiments And this is the first of my two Advertisements The second is this That among the Difficulties I foresaw in making Experiments suited to my Design I look'd upon it as one of the greatest though the least obvious that to satisfy such a Disposition as mine that is naturally prone enough
to question things it would be requisite for me to consider and if I could to determine by appropriated Trials whether the fluid Substances my Experiments might afford me deserv'd the Name of Air or not Wherefore I saw my self oblig'd to increase my Task and so direct my Inquiries that in the first Place they may afford me sensible Portions of such a Substance as in a popular Sense may be stiled Air whether these obtain'd Substances ought to be look'd upon as true Air or no. So that my intended Disquisition would naturally consist of two Parts whereof the former was to contain the ways of producing that which seems Air and the other to propound those of examining how far the produc'd Substance is indow'd with the Qualities that are judg'd to belong to Air as such But in regard that I thought it most convenient so to contrive my Experiments as to make such of them as I could to serve me both to produce Air and to examine it I shall be more than once obliged to mingle the two Parts of my Disquisition and reserve for the latter of them only those few Trials that concern purely the Examen of the produced Air. And upon this Score it will be seasonable to take notice in this Place that forasmuch as there are divers Qualities ascribed to Air which to me seem but accidental and not universally to belong to Air as such I have not observed any one Attribute that I think to be so much the Property of Air and so fit to distinguish its true Particles from aqueous Vapours earthy Exhalations and the Effluvia of other Bodies as a durable Elasticity or Springiness And therefore I shall henceforth imploy that as the chief Criterion whereby to constitute a Portion of Matter Aerial and discriminate it from other flying and fluid Substances and consequently to allow or deny it the Title of Air. Now among the several Ways I thought of whereby to produce Air those I judg'd fittest to put in practice were these 1. By Fermentation 2. By Corrosions and Dissolutions of Bodies 3. By boiling of Water and other Liquors 4. By the mutual Actions of some especially saline Bodies upon one another 5. By the Analyses and Resolutions of certain Substances On January 17 we conveyed into a long and large Tube some Filings of Steel and as much Water as was thought convenient to dilute the Oil of Vitriol which we also conveyed in a peculiarly shap'd Glass seal'd at both Ends but with a Hole opened near one of them the external Tube and the Water in them being exhausted and the Mercury in the Gage which we had also included being so far impelled up into the open Leg that there was scarce any at all left in the seal'd one this I say being done the external Tube was by our way exactly closed and then the Oil of Vitriol being by little and little and at good Intervals of Time poured out of the internal Tube to actuate the Water there were produced exceeding large Bubbles by the Action of the Solvent upon the Metal which also produc'd a sensible Heat though not a great one When this Conflict had lasted a while we observed in compliance with the chief Scope of this Experiment whether there would be any springy Air produced by all those Bubbles and we perceiv'd that there seem'd to be so much of it generated that at length the Mercury in the Gage was impell'd to the very bottom of the open Leg and the Air included in the other seemed to be more compress'd than it had been when it was put in by the Weight of the Atmosphere But to try whether this Spring wherein the Warmth formerly mentioned might be suspected to have for that time some Interest would continue I removed the Tube into another Room where was no Chimny and coming to look on it the next Day did not take notice of any sensible Alteration in the Gage and with the like Success I visited it for three or four Days But then coming one Day to look upon it I found the Mercury in the Gage to have ascended about one Inch and an half and about that quantity of Water to have got into the sealed Leg which inclined me so much the more to suspect that this Change in the Gage might have been accidental a Boy having unknown to me removed the Tube from its wonted Station to place somewhat else there without doing it heedfully enough And this Conjecture seems the more likely because I have not seen any notable Change to have happened in the Gage from that time to this which is the 25th of January at Night the Mercury in the open Leg being about one Inch and an half March 8. A Glass Vial holding about a Pint by guess was filled with Wheat Flower and as much Water as was sufficient to drench it well Afterwards the Orifice was exactly and strongly closed with a Cork and an excellent Cement the Glass was set in a warm Place of the Laboratory because of the Coldness of the Season and having stood there a Fortnight bating one Day it this Morning broke by the mere Dilatation of the included Matter whose visible Part was last Night observ'd to leave a considerable Part unfill'd beneath the Cork Notice was taken by the Laborant of the Event of this Trial by a Noise which yet was no louder than one made upon the bursting of the Glass into several Pieces To my Taste the included Matter was but a little sourish but another afterwards judged it to be manifestly acid March 9. Having on the 23d of February put into a pretty large Bolt-head a convenient Quantity of bruised Raisons with as much Water as I thought necessary to make them ferment and having caused the Air to be carefully pump'd out and taken sufficient Order to keep any from forcing or stealing into the Glass I set it in the Laboratory that the Warmth of the Air might facilitate the Fermentation At the end of four or five Days it did not appear by a Mercurial Gage which had been purposely inclosed together with the Raisons that there was generated any springy Substance But being hindred by several Occasions from looking after this Glass from time to time it seems the contained Liquor fermented more violently than the time of the Year would have made one expect for about four of the Clock in the Afternoon no body being in the Laboratory the Glass flew in pieces with a loud Noise like the Report of a Pistol which alarming a Domestick of mine that was in a Chamber not far off made him hasten to the Laboratory where he found the Raisons thrown all about and the middle part of the Bolt-head for the Bottom and the Pipe were intire enough scattered into such little Pieces that they seemed almost to be vanished On the 22d of February I filled a Glass that had a somewhat wide Mouth and might hold by Estimation three Pints or
Pounds of Water to which that Liquor and a convenient Quantity of bruised Raisons upon the Orifice of the Glass were tied the Neck of a pretty large Bladder out of which the Air having been diligently express'd it was strongly fastned to our Glass with one of our close Cements so that by squeezing the Bladder we could not perceive that any Air could get in or out Then this done we left the Glass in a convenient Place in the Laboratory till the 8th or 9th of March and then finding the Bladder to be pump'd up we would have tied up the contained Air but could not do it by reason of an imperceiv'd Hole perchance made with the Point of a Pin by some one of them that handled it Wherefore taking off this Bladder we caused another that was very limber to be put on after the manner newly described and yesterday Morning we found it though by Estimation it might hold about two Pounds of Water to be so full of Air that we could not without difficulty and losing a pretty deal of the contain'd Air tie the Bladder very close near the Neck of it And to try whether this same Mixture would continue to produce Air whether fermented or not I must not here dispute I caused another Bladder to be fastned to the same Glass as before and found it this Morning March 11. as full as if it were distended with a Pair of Bellows April 28. Into the bottom of a wide-mouth'd Vial we put some good Spirit of Salt and Filings of Steel and whelm'd over it a Rr. fitted with an Eel-skin and a Wire to the latter of which was tied a thin Glass-Vessel hermetically seal'd at the bottom tho 't was but slender and furnished with a competent Quantity of Filings of Copper then we exhausted the Rr. well with our Engine and afterwards by thrusting the Glass that held the Filings against the bottom of the Vial we broke it off upon which the Filings fell into the Menstruum which acting upon them there ensued good store of Bubbles that made a Froth much deeper than was the Liquor and the successive Generation of these Bubbles continued a good while and appear'd some of them large enough though in the free Air they would scarce have been visible or at least would not have been taken notice of the Vial having been kept in our Vacuum for a Quarter of an Hour longer and no Greenness to be seen in the Liquor the Rr. was taken off and the Vial left open to the Air. A Bubble of Air whose Diameter was near in length to that of a middle siz'd Pea was left at the top of a round Vial with a long narrow Neck whose Cavity was fill'd with fine Oil of Turpentine and then being inverted into a Vial fill'd with the same Liquor was set aside in a quiet Place and left there for a competent time Another Vial shap'd like the former but a pretty deal less was fill'd Neck and all with Alcohol of Wine save a Bubble of Air about the same Bigness with the former This Vial being inverted into another furnish'd with the same Liquor was set aside in the same Window with it and at the same time The Event was that about the End of the 6th Day the Bubble disappear'd in the Glass that contain'd the Oil of Turpentine And the like Absorption if I may so call it I observ'd to have been made of the Air by the contiguous Spirit of Wine the next Day after May the 23d We open'd another exhausted Receiver wherein was an unstop'd Vial more than half full of an opacous and blackish Liquor which we guess'd for we found no Inscription belonging to it to have been Frogs Spawn and were sure to have been included at least three Years By the Mercurial Gage that was put up with it it appear'd to have afforded some Air but not very much It s Smell was stinking much like that of the Pump of a Ship but yet it had produc'd no Insects nor had any Appearance of Mouldiness A Gentleman of my Acquaintance an industrious Digger for Mines and Owner of a good one informs me that when the Miners meet with running Water under Ground they are thereby supplied with Air enough for free Respiration And when I ask'd whether he thought that Air was produced or extricated by the Motion of the Water or else were only concomitant to the Stream He answered that it seemed to him more like to proceed from the Water it self and further answered me that standing Waters did not afford Air to the Diggers and that running Waters did it even at considerable Depths amounting to many Fathoms Experiments about the Production of Air and the examining thereof proposed Sect 1. TO produce Air by Fermentation in exactly closed Receivers To produce Air by Fermentation in seal'd Glasses To separate Air from Liquors by boiling To separate Air from Liquors by the Engine To produce Air by Corrosion especially with Sp. Anti. To separate Air by Animal and sulphureous Solvents To obtain Air in the exhausted Receiver by burning Glasses and red hot Irons To produce Air out of Gun-powder and other nitrous Bodies Sect. 2. Examine the produc'd Aerial Substance by its preserving or reviving 1st Animals 2dly Flame 3dly Fire 4thly The Light of rotten Wood Fish To examine it by its Elasticity and the Duration thereof As also by its Weight And by its lifting up the Smoak of Liquors TITLE VII Of the Accidental or less constant Ingredients of the Air. Â TITLE VIII Of Aqueous Particles in the Air and of the Moisture and Driness of the Air. I Shall not here determine whether in all the Instances that are referr'd to this Title the Phenomena be produced by the meer Moisture of the Air as such or by some other Agents whose Corpuscles are accompanied and assisted by the moist Air as a Vehicle and a concurrent Cause But without nicely distinguishing the Grounds of particular Operations we shall refer the Phenomena in general to the Moisture of the Air or moist Air that Quality being the most obvious to be observ'd in these Phenomena in the Production of some of which it seems either the only or the main Cause in others an assistant Cause and in all a not useless Concomitant The Account upon which a Body is dry being usually but this that the Pores intercepted between its more stable Parts are not fill'd with any visible Liquor it is not to be expected that a Quality so near of kin to a Privation should furnish much to our present historical Notes But yet Driness may sometimes have a not-inconsiderable Interest in the Changes of a Body and that upon differing Scores whereof I take these two to be the chief 1st As the Body by Exsiccation is deprived of those liquid and exhalable Parts that were before harbour'd in its Pores and were perhaps the Principle of divers Operations ascribed to it And 2dly As these Evaporable Parts
by their Recess may occasion a Change of Texture in the Body especially in regard of the Pores whose Bigness Figure and perhaps Position being alter'd the Body by this Change of Texture acquires a Disposition to act and be acted on in several Cases otherwise than formerly Sometimes when the Weather began to be overcast the Hygroscope did not sensibly appear to grow heavier and sometimes it would preponderate when I took notice of no Vapours to make it do so and though these things happen'd but seldom in respect of the ordinary Changes of the Hygroscope according to those of the Weather yet they made me suspect that sometimes the Clouds may consist of other Steams than Aqueous or that there may be some Exhalations that may have a peculiar Congruity with the Pores of the Hygroscope and whose Nature may be such as to the Power of drying the Hygroscope that upon these or some other yet unheeded Accounts the Steams that are sometimes diffused in the Air may controul the usual and regular Causes of increasing or lessening the Gravity of the Hygroscope And this Suspicion was the stronger because having made Hygroscopes with Powder and Salt and also with the Saw-dust of Wainscot hung at nice Scales in very thin open Glasses purposely blown for Lightness sake at the Flame of a Lamp though they usually acquired and lost Weight as the Weather grew moister or drier yet sometimes they did not At half of an Hour after nine a Clock at Night I look'd upon the Half Hundred Weight that hung at the bottom of the Rope the Weather being then fair and a Mark being put at that part of the erected Board where the bottom of the Weight touch'd I perceiv'd the Sky a while after to grow cloudy and overcast but without Rain wherefore going to visit the Weight again I found it to be risen ¼ of an Inch or more and looking on my Watch perceiv'd there had pass'd an Hour and a Quarter since the Mark was made This Morning I came again to look upon the Weight between eight and nine of the Clock and found it raised above the newly mentioned Mark made last Night about one Inch for 't was about 9 10 of an Inch. This Day the Weather being fair and windy the Weight was fallen by ten at Night about six Inches beneath its Station at which I found it when I look'd on it in the Morning Being not well yester-night the Weight was observ'd at Bed-time by two of my Servants and it then rested at the 11th of the erected Bound This Morning about eight of the Clock I visited it my self and found it to be risen about ⅛ of an Inch above the eighth Inch the Morning being cloudy though the Morning very dry and dusty The Weather growing more overcast within somewhat less than an Hour after I visited the Weight again some scatter'd Drops of Rain then beginning to fall and found it to be risen about half an Inch above the newly mention'd eighth Mark. I look'd when I was ready to go to Bed upon the suspended Weight of 56 Pound and mark'd how low it reach'd upon the divided Board and a great part of the Night having been rainy I look'd again when I was dress'd in the Morning which was about half an Hour after eight a Clock and I found the Cord so shrunk that the Weight was raised above five Inches higher than I left it the Night before but the Day recovering dry and windy and sometimes warm the Rope was so stretch'd that at Night the Weight sunk a good way beneath all the Marks N. B. The Rope near the Weight was in Diameter ◠of an Inch and four decimal Parts of a tenth We took a Rope of near three Foot and an half in length from the Point of Appension and somewhat less than ◠Inch in Diameter this we suffer'd to be stretch'd for some Days by a Weight of Lead with an Iron Ring or Ansula weighing a Quarter of an Hundred according to the great Hundred which is five score and twelve and then placing a flat Board under it so that the Weight just rested upon it we had the Rope well wetted over them with a Spunge dip'd in Water and so often applied to it that the Liquor might be thorowly soak'd into the Pores of the Rope which at first seem'd thereby a little stretch'd rather than shorten'd but after an Hour or two it began to shrink so that we could make the Weight swinge like a Pendulum over the Piece of Board it lean'd upon before But afterwards the same Day the Weight stretch'd out the Rope again as much as formerly 'T is observable that though Morocco be an Inland-Town and the Soil of those Parts be usually dry if not parched yet Doctor D. who was lately there informed me that about Morocco notwithstanding the violent Heats he felt in the Day-time he observed the Nocturnal Air to be very damp so as to make the Clothes he put off at Night exceeding moist and unfit to be worn without airing the next Morning He added That though the Air was very piercing and manifested it self to be so by many other Signs yet it would not make his Knife rust in his Pocket or his Sword in the Scabbard though it would quickly produce a Rust in Instruments of that Metal exposed naked to it Air too moist cannot be wholesome The Air in our Parts viz. about Oakly in Buckingham-shire though a high Country is as I said before between Michaelmas and Alhallontide very moist especially in rainy Weather and upon a Thaw insomuch that Wainscots Stair-cases and Pictures will stand all of a Water and after run down in great Drops and at Brill upon that high Hill 't is in divers Houses worse than in the Valley insomuch that the Stair-cases especially if laid in Oil will run down with Water the North and North-East side of our Houses are observed to be moister insomuch that the Furniture will rot if Fires be not made sometimes in the Rooms and the things aired This is observ'd to be the most aguish Season of the Year Mr. J. T. As in another Experiment wetried whether or no the Removal of the Air out of the Receiver would much alter the Temperature of the included Medium or Space as to Heat and Cold so we indeavour'd to discover whether the Alteration would be notable as to Driness and Moisture To this purpose we did indeed wish for such a Hygroscope or Instrument wherewith to measure the Moisture and Driness of the Air as we used many Years ago and since found well described by the industrious Kircher in a Place of his Ars magnetica to which I therefore refer your Lordship But in regard that to this Instrument there is requisite the Beard of a wild Oat seasonably gather'd which we could not then procure we recall'd to Mind another Hygroscope which though it discover not such small Mutations as the former we thought
divers of them grant indeed that the Atmosphere is not absolutely pure but yet think that it differs but gradually from true and simple Air as Water a little moved and troubled does from clear and settled Water But for my part I confess I acquiesce not in either of those Notions of the Air. For as I have elsewhere more fully declared in a short Discourse purposely treating of the Substance of the Air although I will not deny that there is an Ethereal Matter more subtile than the common Air which Ether I take to be diffused through all the Interstellar Part of the Universe known to us reaching to and surrounding all its great Globles yet speaking of the Air which we Men live and breath in I take our Atmosphere to consist not only of the purer Ether but in great part of a vast multitude of Effluvia emitted by the Terraqueous Globe and the various Bodies it is made up of and perhaps in some part also of substantial Emanations from the Celestial Bodies and that that whereby the Atmosphere differs from such pure Air as the Schools tell us of is not a bare and indeterminate Feculency but a confused Aggregate of several distinct and perhaps disagreeing kinds of Effluvia And amongst those one of the principal sorts I take to be the Saline ones which rove up and down amongst others in that vast Ocean of Effluxions we call the Atmosphere wherein yet I do not think there are to be met with either all sorts of them every where or perhaps any sort in like Plenty in all Places and at all Seasons To shew that the Air is not unfurnished with Parts of a saline Nature I might alledg some Considerations that seem to make it probable à priori as they speak that there are always some such Corpuscles emitted into the Air. But instead of insisting on such Particulars because they may seem too little of an Historical Nature to be fit for this Paper I shall content my self to take notice in the general that almost if not more than almost all the Arguments I have employed to prove the copious Ascension of subterraneal Steams into the Air may be applied to our present Purpose since amongst the effluviating Substances of the Terraqueous Globe there are as I have declared in another Paper huge quantities of common or Marine Salt besides Nitrous Aluminous Vitriolate and perhaps other kinds of Salts To which I shall add that the emission of Subterraneal Aporrheas or Effluxes is not the only Means whereby the Air may be impregnated with saline Particles since the Exhalations and Vapours produced by the Action of the Sun-beams upon the more superficial Parts of the Earth and Sea may supply the Air with Swarms of Corpuscles as well of saline as of any other Nature Not to mention that the Number of these may in divers Places be much increased by those Vulcans that have open Vents to discharge their Fumes into the Air by those numerous Fires which burning in our Chimnies produce much saline Smoak and by other ways which I shall here forbear to discourse of for the Reason lately given for my declining Arguments drawn à priori though some things applicable to this purpose will in likelihood occur amongst the Instances I am about to add to make it seem probable à posteriori or by some Effects and Phenomena that the Air is impregnated with saline Corpuscles that are none of its least active Parts and may have great Interest in divers of its Operations From what has been hitherto delivered to make it probable that there is a saline Substance in the Air I thought fit to proceed to other Inquiries The first Whether the Aerial Salts be of differing kind and if so which they are And the second How it comes by its saline Substance But about such differing Points I durst promise my self but little Satisfaction and therefore shall not pretend to give you much And yet to say something to the first of the two Inquiries I am prone to think that the saline Particles of the Atmosphere are not all of one sort but that there may be three or four differing kinds of Aerial Salts I know that divers learned Men some Physicians some Chymists and some also Philosophers speak much of a Volatile Nitre that abounds in the Air as if that were the only Salt wherewith it is impregnated But though I agree with them in thinking that the Air is in many Places impregnated with Corpuscles of a Nitrous Nature yet I confess I have not been hitherto convinc'd of all that is wont to be delivered about the Plenty and Quality of the Nitre in the Air For I have not found that those that build so much upon this volatile Nitre have made out by any competent Experiment that there is such a volatile Nitre abounding in the Air. For having often dealt with Salt-peter in the Fire I do not find it easy to be raised by a gentle Heat and when by a stronger Fire we distil it in close Vessels 't is plain that what the Chymists call Spirit of Nitre has quite differing Properties from crude Nitre and from those that are ascribed to the volatile Nitre of the Air these Spirits being so far from being refreshing to the Nature of Animals that they are exceeding corrosive And even when I caused Earth to be dug up in an old Pigeon-House because that is accounted the most nitrous sort of Earth and distill'd it with moderate Fires I did not find the volatile saline Parts that came over to be like that which these learned Men conceive the Air to be stored with Nor have I met with among them any positive Proof to evince the Truth of their Opinion which yet as I was saying I am content to admit as an ingenious Supposition 'till something be offered that shall prove it to be more which I think not impossible to happen at least as to some Times and Places But I am not yet sure that the Exhalations that ascend from the subterraneal Parts and perhaps also the Sun-Beams themselves may volatilize many of the nitrous Corpuscles they chance to act upon and elevate them into the Air without analyzing them or destroying their Texture as our Fires are wont to do But however I do not take the hitherto mention'd Nitre to be the only Salt that impregnates the Air For when I consider how vast a Portion of the Terraqueous Globe is cover'd with the salt Sea and how vast Quantities of fossile Salt as well fine and clear as course are dug up in Poland especially near Cracovia in Hungary Transylvania and in divers other Parts of the Earth When I consider too that we seldom find Salt-peter in the Earth but that there is Sea-Salt mix'd with it which puts the Salt-peter-men to a great deal of Trouble to separate it and that even from Salt-peter that passes for good I had Trouble enough when I had the Curiosity purposely to refine
been solicitous to describe the fore-mention'd Changes of Colours more particularly because it had been very difficult to do so and therefore I judg'd it more expedient not to attempt it For there is so great a Variety of Colours that few but Painters can exactly enumerate and distinguish them by proper Names And yet besides those more noted ones there are many others for which though our Language nor perhaps any other is not copious enough to furnish us with distinct Appellations yet our Eyes especially when they have been attentively conversant with such Objects are sharp enough to discern them and by the Help of these nameless as well as the stated Colours I am apt to think a heedful Observer may perceive divers Variations in the Colours of the Bodies we have been speaking of that may assist him to guess what Substance it is in the Air whereto these Diversities may be ascribed And as Nature is much more rich in Things than our Dictionaries are in Words so has she furnished Men with Sensories capable of distinctly perceiving a far greater Variety of Objects than they are able verbally to express And this might be shewn by Instances in the Organs and Objects of Senses less acute than Sight whose Subtilty in distinguishing things I could exemplify not only by what is related but by what has been perform'd by some Persons not unknown to me particularly our famous Doctor Harvey But Examples of this kind I have not leisure to stay on and therefore without spending more Words upon this third way of discovering aerial Salts I shall barely recommend the Care of such Observations to their Curiosity who shall think it worth while to make them With how little Confidence of Success Trials that have the Aims of those I have been speaking of are to be attempted not only Consideration but Experience hath made me sensible But yet I would not discourage humane Curiosity from adventuring even upon slight Probabilities where the Nobleness of the Subjects and Scope may make even small Attainments very desirable Those adventurous Navigators that have made Voyages for Discovery in unknown Seas when they first discern'd something of obscure near the Horizon at a great Distance off have often doubted whether what they had so imperfect a Sight of were a Cloud or an Island or a Mountain But though usually it were more likely to be the former as that which more frequently occurr'd than the latter yet they judg'd it advisable to stere towards it till they had attained a clearer Prospect of it For if it were a deluding Meteor they would not however sustain such a Loss in that of no great Labour as in case it were a Country they would in the Loss of what might prove a noble and rich Discovery And if they desisted too soon from their Curiosity they could not rationally satisy themselves whether they slighted a Cloud or neglected a Country I do not perceive that the Air of our Inland Parts is considerably impregnated with Esurine Salt since I do not find the Barrs and Casements of our Windows much impaired by Rust after near eighty Years standing or that they are more rusty towards one Quarter than another though the Air hereabout viz. Oakly in Buckingham-shire is very damp about the End of Autumn and Beginning of Winter So that I conceive this Salt either proceeds from the Sea-Vapours near the Sea-Coasts or else from the Dissolution of this Esurine Salt in the Air upon the burning of Sea or other mineral Coles Mr. J. T. Mox ollam ex igni removent postea ex refrigerata eximunt halinitrum purissimum quod candidi marmoris speciem gerit atque tunc etiam id quod terrenum est in fundo residet At terra ex qua dilutum fuit factum rami quernei vel consimilis arboris alternis sub dio ponantur aqua quae combibit halinitrum conspergantur quò modo quinque vel sex annis rursus apta fit and conficiendum dilutum Halinitrum quodammodo purum quod dum terra tot annos quievit interea ortum fuit quod lapidei parietes in cellis vinariis locis opacis exudant cum primo diluto permistum decoquatur Si verò locus aliquis talium venarum copiam suppeditaverit ipsae statim non conjiciantur in castella sed primo convehantur in areas atque cumulentur quanto enim diutius aeri pluviis expositae fuerint tanto meliores fiunt Nam in ejusmodi cumulis aliquot post mensibus quam venae in areas fuerunt congestae nascuntur fibrae longe venis bonitate praestantes deinde vehantur in sex plurave castella longa lata ad novem pedes ad quinque alta Si verò dum dilutum recoquitur separata non fuerint mox ex minoribus vasis infundatur in majora eaque concludantur in quibus item atramentum sutorium separatum ab alumine concrescit utrumque excisum in hypocausto siccatum divendatur dilutum quod in vasis cupis non concrevit in cortinam refusum recoquatur sed terra quae in fundo cujusque cortinae resedit ablata in castello unà cum venis denuo aqua urina diluatur At terra quae in castellis diluto postquam effluxit superfuit egesta coacervata quotidiè rursus magis ac magis fit aluminosa non aliter atque terra ex quâ halinitrum fuit confectum suo succo plenior fit quare denuo in castella conjicitur aquae affusae ea percolantur A learned Observer who practised Physick in one of the most Southern of the English Colonies being ask'd by me about the Effects of the Air there upon Iron affirm'd to me that the great Guns there are so subject to become rusty that after they have lain a very few Years in the Air one may with a Hammer knock off whole Scales or rather Cakes of Crocus Murtis and he observ'd that those Guns that lay only expos'd to the Air did this much more than those that by Accidents were drown'd and lay cover'd with the salt Water And since Dew is made of Steams of the Terrestrial Globe which whilst they retain that Form and were not yet convened into Drops did swim to and fro in the Air and made part of it the Phenomena that shew the Power of Dew in working on solid Bodies may help to manifest how copiously the Air may be impregnated with subtil saline Parts Wherefore I shall here add that having met with a Person that was bred as well a Scholar as a Traveller and had visited not only some of the maritine Places of Brasil but some of the inward Parts of that vast Country I inquired of him about the Subtilty of Brasilian Dew and its Power to rust Metals about which he told me that it was certainly very great and would not only rust Knives and such Instruments but likewise Money which he assured me he had particularly observed adding
some Design So that I and a Gentleman that bore me Company had a pleasant Scene whilst their Fear to be undermined by us made them disbelieve all we told them and do what we could they would think us craftier Fellows than we were But Sir I will not trouble you with the Particulars of this Adventure but certain it is the Women too were alarm'd and think us still either Projectors or Conjurers Since I could not get down into their Gruffs I made it my Business to inquire what I could concerning them The Workmen could give me very little Account of any thing but what Profit made them seek after they could apprehend no other Minerals but Lead Oar and believed the Earth held nothing else worth seeking for besides they were not forward to be too communicative to one they thought they had Reason to be afraid of But at my Return calling at a Gentleman's House who lives under Minedeep-Hills and who had sent out his Son to invite me in amongst other things he told me this that sometimes the Damps catch them and then if they cannot get out soon enough they fall into a Swound and die in it if they are not speedily got out and as soon as they have them above ground they dig a Hole in the Earth and there put in their Faces and cover them close up with Turfs and this is the surest Remedy they have yet found to recover them In deep Pits they convey down Air by the side of the Gruff in a little Passage from the Top and that the Air may circulate the better they set up some Turfs on the Lee side of the Hole to catch and so force down the fresh Air But if these Turfs be removed to the windy side or laid close over the Mouth of the Hole those below find it immediately by want of Breath Indisposition and Fainting and if they ehance to have any sweet Flowers with them they do not only lose their pleasant Smell immediately but stink as bad as Carrion Notwithstanding this ill Success I had attempted some Trials once more had not the spreading of the Contagion made it less safe to venture abroad and hastened me out of the Country sooner than I intended But I have some Hopes the next Journey I make into those Parts to give you a better Account than this that follows Near the House where I sometimes abode was a pretty steep and high Hill April 3. hora inter 8 9. Matutin the Wind West and pretty high the Day warm the Mercury was at 29 Inches and 1 â—â— being carried up to the Top of the Hill it fell to 28 Inches ¾ or thereabouts for I think it was a little above 28 Inches ¾ Both going up and coming down I observed that proportionably as I was higher or lower on the Hill the Mercury fell or rose At my return to the bottom of the Hill the Mercury wanted of ascending to its former Height â— of an Inch which I impute to the Sun 's rarifying some Particles of Air that remained in the upper Part of the Tube rather than to any other Change in the Air for I find it harder to clear the Tube of Air perfectly than at first I thought or of Water if that have been put in with the Mercury and I fear liable to the same Inconvenience with Air inclosed I know this is far short of what you might have expected and has I fear but little answered your Desires since I guess it was the perpendicular Height of the Place I made the Experiment in that you would have had and perhaps other Considerations of Air inclosed and liable to mineral Steams would have made a Trial in one of the Gruffs more acceptable to you I do not think any thing in this Letter worthy of you or fit for the Publick But since I find by the two last Philosophical Transactions that Observations on the Torricellian Experiment are much look'd after and desired to be compared if for want of better this should be thought fit to fill an empty Space in the Philosophical News-Book I shall desire to have my Name concealed But I fear that this very Caution of being in Print where there is no Danger of it has too much of Vanity in it I 'm sure 't is Boldness enough though allaid with Obedience to venture such slight things to your Sight I visited the incrusting Spring I formerly mentioned to you and could not find any thing incrusted within at least 20 Yards of the Rise of it The Place where it works most is about 40 or 50 Yards from the Spring-head and is at a Fall higher than my Head there it sheaths every thing with stony Cases and makes the sides of the Bank hard Rock and from thence all along its Stream it covers Sticks c. with a Crust and some so candied I found above this Fall but not so frequent whether the mixing of Air with the Water in the Fall contributes any thing to the Effect I cannot guess but that the Fall does I suppose for besides that at the above-mentioned Fall it seems to operate most strongly I observed that though I could not find any thing incrusted within a good Distance of the Spring yet that the Moss above the Spring was a little incrusted but not so firmly as at the other Place for the Water in the Winter when the Springs are full runs out also at a Hole two or three Yards above the Place where now only it rises and from thence falls perpendicularly into this lower Spring from whence it runs by an easy Descent to the next Fall A Gentleman in whose Field it rises and by whose House it runs told me upon Inquiry that he uses it both in his Kitchen and Brew-house without any sensible ill Effects he being a pretty ancient but healthy Man and long Inhabitant of that Place It will bear Soap freezes quickly and waters his Grounds upon Occasion with Advantage All the ill Effects of it that he can guess are that his Horses are usually short-breathed which he imputes to the drinking of that Water I brought with me from Minedeepe some Oar and some Stones but I think them so inconsiderable that I shall not judg them worth sending unless you please to command them I am SIR Your most Humble and most Obedient Servant JOHN LOCKE Ch. Ch. 5º May 1666. POSTSCRIPT I had forgot to mention to you that in their Gruffs after burning when they meet with hard Rocks in their way they make a Fire upon them that they may dig through the easier they find it very dangerous to go down into them as long as there remains any Fire or Heat in any Chinks of the Rocks Some Days ago the King doing me the Honour to discourse with me about the Use of Baroscopes was pleased to say among other remarkable things that at a time his Majesty then named he went from Whitehall about six in the Morning towards the
intermix'd with blew Stones which have on them a yellow Rust as that of Copper and Vitriol and likewise many little Springs of vitriolate Waters here he supposes was a Copper-Mine And he was told by a Bell-founder of Oratava that out of two Horse-Loads of Earth he got as much Gold as made two large Rings And a Portuguese told him who had been in the West-Indies that his Opinion was there were as good Mines of Gold and Silver there as the best in the Indies There are likewise hereabouts nitrous Waters and Stones cover'd with a deep Saffron colour'd Rust and tasting of Iron And further he mentions one Mr. Gilbert Lambell a Friend of his who of two Lumps of Earth or Oar brought from the Top of this Side the Mountain made two Silver Spoons All this he confirms from the late Instance of the Palm-Island eighteen Leagues from Teneriff where a Vulcano was fired about twelve Years since the Violence whereof made an Earthquake in this Island so great that he and others ran out of their Houses fearing they would have fallen upon their Heads They heard the Noise of the Torrents of flaming Brimstone like Thunder and saw the Fire as plain by Night for about six Weeks together as a Candle in the Room and so much of the Sand and Ashes brought from thence by the Wind by Clouds fell on his Hat as filled a Sand-box for his Ink-horn Thus far he To resume therefore the Narrative of their Journey about six a Clock this Evening they began to ascend up the Pico but being now a Mile advanced and the way no more passable for their Horses they quitted and left them with their Servants In this Mile's Ascent some of their Company grew very faint and sick and from Dr. Pugh's Report of eighteen in his Company that went up about the middle of August long after this but ten got up and these had all drank very plentifully below the rest so disorder'd by Fluxes Vomitings and aguish Distempers they could go no farther Their Horses Hair stood upright like Bristles with the vehement Cold who stood shaking and refused to eat any thing till they came down But calling for some of their Wine which was carried in small Barrels-on a Horse they found it so wonderfully cold that they could not drink it till they had kindled a Fire to warm it although yet the Temper of the Air was very calm and moderate but when the Sun was set it began to blow with Violence and grew so cold that taking up their Lodging under certain great Stones in the Rocks they were constrained to keep great Fires before the Mouth of them all Night About four in the Morning they began to mount again and being come about a Mile up Mr. Cowling one of the Company failed and was able to proceed no further Here begin the black Rocks The rest pursued their Journey till they arrived to Sugar-Loaf where they begin to travel again in a white Sand being fore-shod with Shoes whose single Soles are made a Finger broader than the upper Leather to incounter this difficult and unstable Passage till they are half way up and a Spaniel that went up afterwards with Dr. Pugh as he relates went crying all the way having his Skin burnt off his Feet and then being ascended as far as the black Rocks which are all flat and lie like a Pavement they climbed within a Mile of the very Top of the Pico but Mr. Clappham who was the formost would have perswaded Mr. Cove to descend again as imagining the Top of all on Fire but at last overcoming that Apprehension and persisting they gained the Summite where they found no such Smoak as appeared a little below but a continual Breathing of a hot and sulphurous Vapour which made their Faces extreamly sore In this Passage they found no considerable Alteration of Air and very little Wind but being at the Top it was so impetuous that they had much ado to stand against it whilst they drank the King's Health and fired each of them a Piece Here they also brake-fast but found their strong-Strong-Waters had quite lost its Force and was become almost insipid whilst their Wine was rather more spirituous and brisk than it was before The Top on which they stood being not above a Yard broad is the Brink of a Pit called the Caldera which they judged to be about a Musket-shot over and near fourscore Yards deep in shape like a Cone within hollow like a Caldron and all over cover'd with small loose Stones mixed with Sulphur and Sand from Heat and stirr'd up with any thing puffs and makes a Noise and so offensive that Dr. Pugh was almost stifled with the sudden Emanation of Vapours upon the removing of one Stone of these these Stones are so hot as they are not to be easily handled They descended not above four or five Yards into the Caldera in regard of its sliding from their Feet and the Difficulty but some have adventured to the Bottom Other observable Materials they discovered none besides a clearer sort of Sulphur which looks like Salt upon the Stones From this famous Pico they could ken the Grand Canaries fourteen Leagues distant Palma 18 and Gomera 7 Leagues which Interval of Sea seemed to them no larger than the River of Thames about London they discerned also the Hierro being distant above twenty Leagues and so to the utmost Limits of the Sea much farther So soon as the Sun appeared the Shadow of the Pico seemed to cover not only the whole Island and the Grand Canaries but the Sea to the very Horizon where the Top of the Sugar-Loaf or Pico visibly appeared to turn up and cast its Shadow into the Air it self at which they were much suprized But the Sun was not far ascended when the Clouds began to rise so fast as intercepted their Prospect both of the Sea and the whole Island excepting only the Tops of the subjacent Mountains which seemed to pierce them through Whether these Clouds do ever surmount the Pico they could not say but to such as are far beneath they sometimes seem to hang above it or rather wrap themselves about it as constantly when the North-West Winds blow This they call the Capp and is a certain Prognostick of ensuing Storms Mr. John Webber one of this Company who had made a Journey two Years after arriving at the Top of the Pico before Day and creeping under a great Stone to shroud himself from the cold Air after a little space found himself all wet and admiring whence it should proceed perceived it at last to come from a perpetual Trickling of the Water from the imminent Rocks above him Many excellent and very exuberant Springs they found issuing from the Tops of most of the other Mountains gushing out in great Spouts almost as far as the huge Pine-tree which was mentioned Having stayed some time upon this Top they all descended by the sandy way till they
something of Illusion offer'd to his Eyes by the Beams of the Sun that shone upon the Neighbouring Objects wherefore he rubb'd his Eyes and the new Scene not vanishing he call'd to his Royal Highness the Duke of York who was present when his Majesty was pleased to make me the Relation and to some of the attending Courtiers that were nearest at hand to make them Partakers and Witnesses of this delightful Spectacle which after it had been gazed on a little while did somewhat slowly disappear as if it had sunk down again into the Ocean Of the Cause of this rare Phaenomenon I ventur'd to propose to the King this Conjecture That the Place where it was seen lying the same way that the Coast of France did and that Coast being but a little too far off to be discern'd before it might very well happen that either by Action of the Sun or rather by subterraneal Steams the Air interposed between the Shore and his Majesties Eyes was fill'd with Vapors and Exhalations that made it much more refractive than formerly and by Help of this supervening Refraction the French Coast that lay beyond it was raised and as it were lifted up in reference to the Sight and so became visible as long as that new Refraction lasted And when the Steams that occasion'd it were either got up too high or were by the Winds or Sun too much dissipated or dispersed the Apparition ceased together with the unusual Refraction that caused it And in favour of this Conjecture I alledg'd that familiar Experiment in which a Piece of Gold or the like convenient Object being put into the bottom of an empty Cup and the Eye being so placed that the Object is but just hid from it by the Interposition of the Side of the Cup if Water be poured into the Vessel though neither the Eye nor the Object be at all removed yet the Piece of Gold will be plainly seen because the Surface of the Water which is a thicker Medium than the Air breaking the Rays that tend from the Object towards the Beholder's Eye according to the Laws of Refraction that is from the Perpendicular they are so bended that those fall now into the Pupil that if it were not for the Water would either fall upon the Side of the Cup and so be hinder'd from passing forward or else would fall upon the Eye-lids or Eye-brows or some other Part above the Pupil and so would not make the Object visible The Duke of York was also pleased to tell me that he was somewhat surprized when being near the Borders of Scotland in a Season that did not promise much fair Weather he saw one Morning the Sky very red and thereupon said that he fear'd they should have foul Weather according to the usual Prognostick of Country-men and Mariners but some of the Scotish Nobility that attended his Highness told him that in that Country such red Mornings did not bode a foul Day but rather promise a fair one which Prediction of theirs was justified by the Event Upon which occasion I enquired of a very intelligent Scotish Noble-man how far the Observation held in his Country To which he answer'd that with a due Limitation it was most commonly true for though when the Redness seems to be very near the Ground and appears in somewhat narrow Streaks of an intense Red it signifies bad Weather yet if the Morning Redness appears elevated in the Air or Sky especially if the Wind be Easterly it usually foretels a fair Day Some Observations of Capt. James in his Northern Voyage Mr. J. T. and others February I practised some Observations by the rising and setting of the Sun calculating the time of his rising and setting by very true running Glasses As for our Clock and Watch notwithstanding we still kept them by the Fire-side in a Chest wrap'd in Clothes yet were they so frozen that they could not go My Observations by these Glasses I compared with the Stars coming to the Meridian By this means we found the Sun to rise twenty Minutes before it should and in the Evening to remain above the Horizon twenty Minutes or thereabouts longer than it should do And all this by reason of the Refraction Capt. James March This Evening the Moon rose in a very long Oval alongst the Horizon April The Weather continued with this Extremity until the fifteenth at which time our Spring was harder frozen than it had been all the Year before I had often observed the Difference betwixt clear Weather and misty refractious Weather in this manner From a little Hill which was near adjoining to our House in the clearest Weather when the Sun shone with all the Purity of Air that I could conceive we could not see a little Island which bare off us South-South-East some four Leagues but if the Weather were misty as aforesaid then we should often see it from the lowest Place This little Island I had seen the last Year when I was on Danby-Island The 13th I took the Height of it instrumentally standing near the Sea-side which I found to be 34 Minutes the Sun being 28 Degrees high This shows how great a Refraction here is Yet may this be noted by the way that I have seen the Land elevated by reason of the refractious Air and nevertheless the Sun hath risen perfect round January 6. I observed the Latitude with what Exactness I could it being very clear Sun-shine Weather which I found to be 51 52. This Difference is by reason that here is a great Refraction January 21. I observed the Sun to rise like an Oval alongst the Horizon I called three or four to see it the better to confirm my Judgment and we all are agreed that it was twice as long as it was broad We plainly perceived withal that by Degrees as it got up higher it also recovered Roundness Attending upon Sir Peter Wych in his Journey for Warsaw the Beginning of June 16 69 70 whilst we lay about three Polish Miles from the City attending the Preparations for his Reception there we had very clear and extream cold Weather and for two Days together we observed the Sun and two Parhelions or three Suns from above ten a Clock to near twelve not the least Cloud appearing in the Air but that so serene that we took notice of the Icy Spangles in the Air flying about like Atoms in the Sun's Beams This is also worth taking notice of that whereas in ordinary frosty Weather any smooth Iron or other Metal whether Heads of Sticks Pomels of Swords or Barrels of Guns being brought out of the open Air into a warm Room there will presently first a Dulness in the Glass and then Drops of Water appear At this time there would immediately appear the Likeness of an hoar Frost Now whether the Particles of Cold be so subtile as to pierce or enter into polished Metal I will not determine tho the Experience of wetting one Finger with his Spittle
Soil and perhaps other Circumstances so that sometimes a Candle would go out much sooner and sometimes it would continue burning though it were let down to the Depth of eight ten or more Fathom That when they come into close Ground though their Candle will burn at first yet after a while working more especially if the Stone be full of Mundick the Dust raised by their Working will make their Candles go out so that they must leave working for a time except they will be at the Charge of conveying down Air by Pipes I mention this as different from other sorts of Damps N. Experiments touching the Relation between Flame Air. THE burning of Candles c. under a Glass Bell. The burning of Spirit of Wine under a Glass Bell. The burning of Match Touch-wood Sponck c. under a Bell. The keeping of Animals under the same Instrument whilst the Flame is burning The burning of Bodies to Ashes in seal'd Glasses The doing the like in exactly closed Receivers The burning of Cotton in a seal'd Glass The burning of the Mixture of Flames under Water in an E. R. The burning of Spirit of Wine and Oil of Turpentine in Glass Vessels with slender Necks The Experiment of burning Gun-Powder Another of the Pistols not firing in an E. R. The burning of a saline Substance in an E. R. The burning of Mixtures of Salt-peter in an E. R. TITLE XXV Of the Air in reference to Fermentation WE took a small handful of Raisons and having put them into a Bolt-head not large but half filled with Water we drew out the Air and then we removed the Portable and exactly closed Receiver and put it on the Digestive Furnace that the Warmth of that Place might promote the Fermentation in spight of the Unfavourableness of the Season of the Year After a while there appeared Signs of Fermentation by the emerging of the Raisons which swan for some Days on the Top of the Water most of them beset with numerous Bubbles nor did above very few of them subside at last though after some Days the Bubbles grew fewer and fewer and there appeared a Sediment at the Bottom of the Glass A Fortnight after they were first sealed up the upper part of the Glass was accidentally broken whilst I stood by whereupon the external Air rushed in with some Noise and I taking the Vessel in my Hand perceived the Surface of the Liquor to be overspead with Bubbles almost like the Forth of Bottle-Drink there seem'd to me to come out at the little Orifice made where the Apex was broken off a visible Fume which had a somewhat languid Smell The Liquor was high colour'd of the Raisons and seem'd to have extracted something from them that gave it a better Consistence than that of Water TITLE XXVI Of the Air as the Receptacle of Odours  TITLE XXVII Of the Operation of the Air on the Odours of Animal Substances MAY 23. We opened an exhausted Receiver wherein was pretty Store of Verjuice or green and sour Grapes And though they had lain there we are sure about three Years and possibly much longer yet there appear'd no Mouldiness at all upon any of them But the Surfaces of the uppermost Grains were somewhat discoloured perhaps by a saline and confusedly formed Efflorescence which having look'd upon through a Glass and also tasted I guessed to be a kind of Tartar The like Liquor that the Grains had afforded had an acid Taste and would in the Cold corrode Coral but the Grains smell'd somewhat musty In all this time the Verjuice had produced so little Air that we could scarce take notice of it by the Mercurial Gage that had been shut up with it I inquired of my Lord of Sandwich and a couple of Gentlemen that accompanied him whether it be true which is reported of the Purity of the Air at Madrid that though they have no Houses of Office but every Night throw out their Excrements into the Streets yet by the Morning there remains no more Smell of them To which I was answered That 't was true the Excrements were so disposed of but that Madrid is the stinkingst Town they ever came into yet that 't was difficult to discern in the Morning any peculiar Smell of what had been cast into the Street by Night but they jointly affirmed that the Place where the Ambassador's numerous Family resorted to make Water in did not smell of Piss and that they often observed the Dogs and Cats that lay dead in the Streets were deprived of Stench and his Lordship supposed that the Stench of a dead Mule would in few Hours vanish TITLE XXVIII Of the Operation of the Air on the Odours of Vegetable Substances MAY 16. At the same time we opened another small Receiver wherein above three Years before some large Pieces of Orange had been included The Rinds of these were much discolour'd their Surfaces being almost black They had scarce afforded any Liquor and yet we could not perceive the least Mould in any of them nor had they a putrid Smell TITLE XXIX Of the Operation of the Air on the Odours of Mineral Substances  TITLE XXX Of the Operation of the Air on the Tastes of Animal Substances HE answered me that they could very well preserve Meat as Beef without salting it as long as the Frost lasted that is during the whole Winter But when it was once thorowly frozen they could not dress it so as to make it relish like good Meat Mr. Nickson TITLE XXXI Of the Operations of the Air on the Tastes of Vegetable Substances  TITLE XXXII Of the Operations of the Air on the Tastes of Mineral Substances  TITLE XXXIII Of the Operations of the Air on the Colours of Animal Substances ENquiring of a Man of Letters that had the Curiosity to travel into the Inland Parts of Brasil whether in that Countrey the Air had not a great Influence upon the Colours of Clothes He told me it had and even upon Black insomuch that a kind of black Taffety which is the usual wear of the better sort will after it hath been worn a very few Days degenerate into an Ironish Colour yet he answered me that in the Shops where 't is carefully kept from the Air the Taffety continued of a good Black Nor is it only upon the Colour of Stuffs but of Animals too that he says the Brasilian Air has an Operation for he says that at a Place 50 Leagues beyond Parigna there is a Region where white People do in a very short time grow Basannez or tawny though a little way out of that particular Region as for Instance beyond it they quickly recover their wonted Colour He told me that upon Charleton Island they have Flocks of certain Birds which the English there call Partridges though they resemble ours more in Bulk than Shape being somewhat like wild Pigeons but a good deal bigger These he says are white in the Winter and gray in the
it into Particles of quite another Nature which by this means are deprived of all their offensive Smell and some other ill Qualities It may also be said that the great Increase of Heat in July may enable the Sun-beams by penetrating the Earth deeper and agitating its lower Parts stronger and producing Crevisses and other new or formerly obstructed Passages in the upper Parts of it may elevate into the Air divers saline and other new Corpuscles which may either divide or dissipate the Pestilential ones or else by associating themselves with them make up new Concretions differing from the Pestilential Corpuscles in Bulk Shape Texture or Motion in most or all of these by which means the morbifick Corpuscles being much altered their Operations on the humane Bodies they invade may be so too and the Diseases they produce may become less malignant or degenerate into some other Disease And if it be demanded why this does not happen elsewhere as well as at Aleppo and Smyrna it may be answered That the Concourse of Causes may not be the same and particularly that the Soil of those two Places may be peculiarly disposed to emit Pestilential Corpuscles of such a determinate Nature with such a Degree of Heat and dissipable by a greater or with a more intense Heat to afford also Exhalations capable to correct the former as 't is delivered by good Authors and ingenious Men have confirmed it upon their own Observation that yearly at Grand Cairo in the Heat of Summer the Plague ceases to be mortal and almost to be infectious when the Nile begins to overflow which wonderful Change I should not so much ascribe to a Frigeration of the Air that usually accompanies the Swellings of the Waters since Pestilences rage in much cooler Weather than can be supposed in so hot a Climate as that of Egypt in July as to some nitrous and other corrected Exhalations that are plentifully emitted by the freshly arriving Waters There is an Account that has not that I know of been taken notice of upon which the supervening Coldness and Heat of the Air may pro tempore very much alter the Qualities of it in reference to the Bodies and Health of Men For the Air being a fluid Body as well as Water and impregnated with Salts of different kinds some merely saline and others associated with sulphureous and other kinds of Particles it seems not improbable that what happens in that grosser fluid Water impregnated with differing sorts of Salts and alter'd by succession of Heat and Cold takes place also in the Air. I purposely tried in Water that by dissolving in it convenient Quantities of two differing Salts though whilst the Liquor was hot or perhaps so much as lukewarm they would swim together undistinguishably in the Liquor and so were in a Capacity to act jointly and as the Schools speak actione communi on divers Occasions yet when the Liquor was cold and sometimes when there was only a considerable Remission of the Heat the saline Particles of one kind being not capable of being any longer sufficiently agitated by so faint a Degree of Heat would convene into Grains or Cristals and losing their Fluidity and Motion visibly separate themselves from the other kind of Salts which yet continued fluid in the Water where it could now act but by its own particular Qualities and not as formerly actione communi The clearest Instance I found of this Observation was afforded me by an Experiment made with the Solutions of Alum and Nitre a Relation of which I find among my Adversaria in the following terms Equal Parts of Alum and Nitre being dissolv'd in the same Portion of fair Water and the Liquor being in good measure evaporated the Earthen Vessel that contain'd it was set in the cold by which means at the bottom and the lower part of the sides the Alum appear'd to be first coagulated in many Octaedrical Grains no Chrystals of Nitre yet being visible Afterwards upon a further Evaporation of the Water and the Removal of the Vessel from the Fire there appear'd more Grains of Alum but as yet no Nitre wherefore having yet further evaporated the Liquor at length the Nitre shot plentifully into fine little Chrystals of the Shape proper to that Salt This is the Account my Note-Book contains of this Trial which seems to invite us to conjecture that of the numerous sorts of saline Corpuscles that rove up and down in the Air whilst it is well heated by the Sun or other Causes some sorts may by the Absence of that Heat or some supervening Causes of Coldness be made to separate from the others which were thereby contemperated or perhaps enabled to co-operate to divers Purposes that they were not fit for alone and to form Concretions which though not singly visible may be too great to be kept in a State of Fluidity by the diminish'd Heat of the Air. A Mouse lived ten Minutes at least with a quarter Air and three afterwards TITLE XLI Of heavy Bodies sustained in or taken up into the Air.  TITLE XLII Of Dew  TITLE XLIII Of Rain AN eminent Virtuoso informed me that in the Country of Campen he had seen divers Pits that are digg'd for Turf or rather Peat which were not deep for the most part but reach'd to a kind of quick Sand upon which the Rain falling did by Degrees in some Years form a kind of slimy Earth or Clay which was much of a martial Nature and being skilfully handled would yield good Iron The same Person assured me that he had divers times distilled the Water of Campen in new and fine Glasses and still found them to leave a considerable Quantity of stony Matter at the Bottom notwithstanding the Rectification Quicquid erit sine fuco significat velut Rottenberg Silesiae compastum appellant perinde Milessow Temporum prognostes jure merito dici posset Vidi ex proximo totum aliquando montem densissimis Nebulis contectum eâ prorsus imagine qua Mons Sinai Moyse in Nebula latente depingitur at caeteri circum Montes innubes hilares velut rerum gerendarun ignari stabant Sol ipse formosissimus ibat at accolae locorum domum fugiebant pecora urgebant meque ut domum protinus recipirem properarem equos currum trahentes concitari juberem monebant neque horae quadrans intercessit jam Coelum obduci Sol contegi eripi omnis aspectus Virg. Immensum Coelo ruit agnem aquarum ruit arduus aether Et pluvia ingenti sata laeta boumque labores Diluit implentur fossae quae divinus Poeta prosequitur At contra etiam accidere vidi ut caeteri fumarint montes Milessow nihil se commovente nihil aut nubilum aut turbidum minante Incoloe rogati nihil esse magnopere timendum à caeteris spondebant hunc unum intuendum esse horum nubila omnia à Milessow quodammodo devorari TITLE XLIV Of Hail ON ecrit de l'Isle en Flandres le