It is the great prerogative of Mankind above other Creatures, that we are not only able to _behold_ the works of Nature, or barely to _sustein_ our lives by them, but we have also the power of _considering_, _comparing_, _altering_, _assisting_, and _improving_ them to various uses. And as this is the peculiar priviledge of humane Nature in general, so is it capable of being so far advanced by the helps of Art, and Experience, as to make some Men excel others in their Observations, and Deductions, almost as much as they do Beasts. By the addition of such _artificial Instruments_ and _methods_, there may be, in some manner, a reparation made for the mischiefs, and imperfection, mankind has drawn upon it self, by negligence, and intemperance, and a wilful and superstitious deserting the Prescripts and Rules of Nature, whereby every man, both from a deriv’d corruption, innate and born with him, and from his breeding and converse with men, is very subject to slip into all sorts of errors.
The only way which now remains for us to recover some degree of those former perfections, seems to be, by rectifying the operations of the _Sense_, the _Memory_, and _Reason_, since upon the evidence, the _strength_, the _integrity_, and the _right correspondence_ of all these, all the light, by which our actions are to be guided is to be renewed, and all our command over things is to be establisht.
It is therefore most worthy of our consideration, to recollect their several defects, that so we may the better understand how to supply them, and by what assistances we may _inlarge_ their power, and _secure_ them in performing their particular duties.
As for the actions of our _Senses_, we cannot but observe them to be in many particulars much outdone by those of other Creatures, and when at best, to be far short of the perfection they seem capable of: And these infirmities of the Senses arise from a double cause, either from the _disproportion of the Object to the Organ_, whereby an infinite number of things can never enter into them, or else from _error in the Perception_, that many things, which come within their reach, are not received in a right manner.
The like frailties are to be found in the _Memory;_ we often let many things _slip away_ from us, which deserve to be retain’d, and of those which we treasure up, a great part is either _frivolous_ or _false_; and if good, and substantial, either in tract of time _obliterated_, or at best so _overwhelmed_ and buried under more frothy notions, that when there is need of them, they are in vain sought for.
The two main foundations being so deceivable, it is no wonder, that all the succeeding works which we build upon them, of arguing, concluding, defining, judging, and all the other degrees of Reason, are lyable to the same imperfection, being, at best, either vain, or uncertain: So that the errors of the _understanding_ are answerable to the two other, being defective both in the quantity and goodness of its knowledge; for the limits, to which our thoughts are confin’d, are small in respect of the vast extent of Nature it self; some parts of it are _too large_ to be comprehended, and some _too little_ to be perceived. And from thence it must follow, that not having a full sensation of the Object, we must be very lame and imperfect in our conceptions about it, and in all the proportions which we build upon it; hence, we often take the _shadow_ of things for the _substance_, small _appearances_ for good _similitudes_, _similitudes_ for _definitions;_ and even many of those, which we think, to be the most solid definitions, are rather expressions of our own misguided apprehensions then of the true nature of the things themselves.
The effects of these imperfections are manifested in different ways, according to the temper and disposition of the several minds of men, some they incline to _gross ignorance_ and stupidity, and others to a _presumptuous imposing_ on other mens Opinions, and a _confident dogmatizing_ on matters, whereof there is no assurance to be given.
Thus all the uncertainty, and mistakes of humane actions, proceed either from the narrowness and wandring of our _Senses_, from the slipperiness or delusion of our _Memory_, from the confinement or rashness of our _Understanding_, so that ’tis no wonder, that our power over natural causes and effects is so slowly improv’d, seeing we are not only to contend with the obscurity and _difficulty of the things_ whereon we work and think, but even the _forces of our own minds_ conspire to betray us.
These being the dangers in the process of humane Reason, the remedies of them all can only proceed from the _real_, the _mechanical_, the _experimental_ Philosophy, which has this advantage over the Philosophy of _discourse_ and _disputation_, that whereas that chiefly aims at the subtilty of its Deductions and Conclusions, without much regard to the first ground-work, which ought to be well laid on the Sense and Memory; so this intends the right ordering of them all, and the making them serviceable to each other.
The first thing to be undertaken in this weighty work, is a _watchfulness over the failings_ and an _inlargement of the dominion_, of the Senses.
To which end it is requisite, first, That there should be a _scrupulous_ choice, and a _strict examination_, of the reality, constancy, and certainty of the Particulars that we admit: This is the first rise whereon truth is to begin, and here the most severe, and most impartial diligence, must be imployed; the storing up of all, without any regard to evidence or use, will only tend to darkness and confusion. We must not therefore esteem the riches of our Philosophical treasure by the _number_ only, but chiefly by the _weight_; the most _vulgar_ Instances are not to be neglected, but above all, the most _instructive_ are to be entertain’d; the footsteps of Nature are to be trac’d, not only in her _ordinary course_, but when she seems to be put to her shifts, to make many _doublings_ and _turnings_, and to use some kind of art in indeavouring to avoid our discovery.
The next care to be taken, in respect of the Senses, is a supplying of their infirmities with _Instruments_, and, as it were, the adding of _artificial Organs_ to the _natural_; this in one of them has been of late years accomplisht with prodigious benefit to all sorts of useful knowledge, by the invention of Optical Glasses. By the means of _Telescopes_, there is nothing so _far distant_ but may be represented to our view; and by the help of _Microscopes_, there is nothing so _small_, as to escape our inquiry; hence there is a new visible World discovered to the understanding. By this means the Heavens are open’d, and a vast number of new Stars, and new Motions, and new Productions appear in them, to which all the antient Astronomers were utterly Strangers. By this the Earth it self, which lyes so neer us, under our feet, shews quite a new thing to us, and in every _little particle_ of its matter; we now behold almost as great a variety of Creatures, as we were able before to reckon up in the whole _Universe_ it self.
It seems not improbable, but that by these helps the subtilty of the composition of Bodies, the structure of their parts, the various texture of their matter, the instruments and manner of their inward motions, and all the other possible appearances of things, may come to be more fully discovered; all which the antient _Peripateticks_ were content to comprehend in two general and (unless further explain’d) useless words of _Matter_ and _Form_. From whence there may arise many admirable advantages, towards the increase of the _Operative_, and the _Mechanick_ Knowledge, to which this Age seems so much inclined, because we may perhaps be inabled to discern all the secret workings of Nature, almost in the same manner as we do those that are the productions of Art, and are manag’d by Wheels, and Engines, and Springs, that were devised by humane Wit.
In this kind I here present to the World my imperfect Indeavours; which though they shall prove no other way considerable, yet, I hope, they may be in some measure useful to the main Design of a _reformation_ in Philosophy, if it be only by shewing, that there it not so much requir’d towards it, any strength of _Imagination_, or exactness of _Method_, or depth of _Contemplation_ (though the addition of these, where they can be had, must needs produce a much more perfect composure) as a sincere _Hand_, and a _faithful_ Eye, to examine, and to record, the things themselves as they appear.
And I beg my Reader, to let me take the boldness to assure him, that in this present condition of knowledge, a man so qualified, as I have indeavoured to be, only with resolution, and integrity, and plain intentions of imploying his _Senses_ aright, may venture to compare the reality and the usefulness of his services, towards the true Philosophy, with those of other men, that are of much stronger, and more acute _speculations_, that shall not make use of the same method by the Senses.
The truth is, the Science of Nature has been already too long made only a work of the _Brain_ and the _Fancy_: It is now high time that it should return to the plainness and soundness of _Observations_ on _material_ and _obvious_ things. It is said of great Empires, That _the best way to preserve them from decay, is to bring them back to the first Principles, and Arts, on which they did begin_. The same is undoubtedly true in Philosophy, that by wandring far away into _invisible Notions_, has almost quite destroy’d it self, and it can never be recovered, or continued, but by returning into the same _sensible paths_, in which it did at first proceed.
If therefore the Reader expects from me any infallible Deductions, or certainty of _Axioms_, I am to say for my self, that those stronger Works of Wit and Imagination are above my weak Abilities; or if they had not been so, I would not have made use of them in this present Subject before me: Whenever he finds that I have ventur’d at any small Conjectures, at the causes of the things that I have observed, I beseech him to look upon them only as _doubtful Problems_, and _uncertain ghesses_, and not as unquestionable Conclusions, or matters of unconfutable Science; I have produced nothing here, with intent to bind his understanding to an _implicit_ consent; I am so far from that, that I desire him, not absolutely to rely upon these Observations of my eyes, if he finds them contradicted by the future Ocular Experiments of sober and impartial Discoverers.
As for my part, I have obtained my end, if these my small Labours shall be thought fit to take up some place in the large stock of _natural Observations_, which so many hands are busie in providing. If I have contributed the _meanest foundations_ whereon others may raise nobler _Superstructures_, I am abundantly satisfied; and all my ambition is, that I may serve to the great Philosophers of this Age, as the makers and the grinders of my Glasses did to me; that I may prepare and furnish them with some _Materials_, which they may afterwards _order_ and _manage_ with better skill, and to far greater advantage.
The next remedies in this universal cure of the Mind are to be applied to the _Memory_, and they are to consist of such Directions as may inform us, what things are best to be _stor’d up_ for our purpose, and which is the best way of so _disposing_ them, that they may not only be _kept in safety_, but ready and convenient, to be at any time _produc’d_ for use, as occasion shall require. But I will not here prevent my self in what I may say in another Discourse, wherein I shall make an attempt to propose some Considerations of the manner of compiling a Natural and Artificial History, and of so ranging and registring its Particulars into Philosophical Tables, as may make them most useful for the raising of _Axioms_ and _Theories_.
The last indeed is the most _hazardous_ Enterprize, and yet the most _necessary_; and that is, to take such care that the _Judgment_ and the _Reason_ of Man (which is the third Faculty to be repair’d and improv’d) should receive such assistance, as to avoid the dangers to which it is by nature most subject. The Imperfections, which I have already mention’d, to which it is lyable, do either belong to the _extent_, or the _goodness_ of its knowledge; and here the difficulty is the greater, least that which may be thought a _remedy_ for the one should prove _destructive_ to the other, least by seeking to inlarge our Knowledge, we should render it weak and uncertain; and least by being too scrupulous and exact about every Circumstance of it, we should confine and streighten it too much.
In both these the middle wayes are to be taken, nothing is to be_ omitted_, and yet every thing to pass a _mature deliberation_: No _Intelligence_ from Men of all Professions, and quarters of the World, to be _slighted_, and yet all to be so _severely examin’d_, that there remain no room for doubt or instability; much _rigour_ in admitting, much _strictness_ in comparing, and above all, much _slowness_ in debating, and _shyness_ in determining, is to be practised. The _Understanding_ is to _order_ all the inferiour services of the lower Faculties; but yet it is to do this only as a _lawful Master_, and not as a _Tyrant._ It must not _incroach_ upon their Offices, nor take upon it self the employments which belong to either of them. It must _watch_ the irregularities of the Senses, but it must not go before them, or _prevent_ their information. It must _examine_, _range_, and _dispose_ of the bank which is laid up in the Memory: but it must be sure to make _distinction_ between the _sober_ and _well collected heap_, and the _extravagant Ideas_, and _mistaken Images_, which there it may sometimes light upon. So many are the _links_, upon which the true Philosophy depends, of which, if any one be _loose_, or _weak_, the whole _chain_ is in danger of being dissolv’d; it is to _begin_ with the Hands and Eyes, and to _proceed_ on through the Memory, to be _continued_ by the Reason; nor is it to stop there, but to _come about_ to the Hands and Eyes again, and so, by a _continual passage round_ from one Faculty to another, it is to be maintained in life and strength, as much as the body of man is by the _circulation_ of the blood through the several parts of the body, the Arms, the Feet, the Lungs, the Heart, and the Head.
If once this method were followed with diligence and attention, there is nothing that lyes within the power of human Wit (or which is far more effectual) of human Industry, which we might not compass; we might not only hope for Inventions to equalize those of _Copernicus_, _Galileo_, _Gilbert_, _Harvy_, and of others, whose Names are almost lost, that were the Inventors of _Gun-powder_, the _Seamans Compass_, _Printing_, _Etching_, _Graving_, _Microscopes_, &c. but multitudes that may far exceed them: for even those discoveries seem to have been the products of some such method, though but imperfect; What may not be therefore expected from it if thoroughly prosecuted? _Talking_ and _contention of Arguments_ would soon be turn’d into _labours_; all the fine _dreams_ of Opinions, and _universal metaphysical natures_, which the luxury of subtil Brains has devis’d, would quickly vanish, and give place to _solid Histories_, _Experiments_ and _Works._ And as at first, mankind _fell_ by _tasting_ of the forbidden Tree of Knowledge, so we, their Posterity, may be in part _restor’d_ by the same way, not only by _beholding_ and _contemplating_, but by _tasting_ too those fruits of Natural knowledge, that were never yet forbidden.
From hence the World may be assisted with _variety_ of Inventions, _new_ matter for Sciences may be _collected_, the _old improv’d_, and their _rust_ rubb’d away; and as it is by the benefit of Senses that we receive all our Skill in the works of Nature, so they also may be wonderfully benefited by it, and may be guided to an easier and more exact performance of their Offices; ’tis not unlikely, but that we may find out wherein our Senses are deficient, and as easily find wayes of repairing them.
The Indeavours of Skilful men have been most conversant about the assistance of the Eye, and many noble Productions have followed upon it; and from hence we may conclude, that there is a way open’d for advancing the operations, not only of all the other Senses, but even of the Eye it self; that which has been already done ought not to content us, but rather to incourage us to proceed further, and to attempt greater things in the same and different wayes.
’Tis not unlikely, but that there may be yet invented several other helps for the eye, at much exceeding those already found, as those do the bare eye, such as by which we may perhaps be able to discover _living Creatures_ in the Moon, or other Planets, the _figures_ of the compounding Particles of matter, and the particular _Schematisms_ and _Textures_ of Bodies.
And as _Glasses_ have highly promoted our _seeing_, so ’tis not improbable, but that there may be found many _Mechanical Inventions_ to improve our other Senses, of _hearing_, _smelling_, _tasting_, _touching._ ’Tis not impossible to hear a _whisper_ a _furlongs_ distance, it having been already done; and perhaps the nature of the thing would not make it more impossible, though that furlong should be ten times multiply’d. And though some famous Authors have affirm’d it impossible to hear through the _thinnest plate_ of _Muscovy-glass_; yet I know a way, by which ’tis easie enough to hear one speak through a _wall a yard thick_. It has not been yet thoroughly examin’d, how far _Otocousticons_ may be improv’d, nor what other wayes there may be of _quickning_ our hearing, or _conveying_ sound through _other bodies_ then the _Air_: for that that is not the only _medium_, I can assure the Reader, that I have, by the help of a _distended wire_, propagated the sound to a very considerable distance in an _instant_, or with as seemingly quick a motion as that of light, at least, incomparably swifter then that, which at the same time was propagated through the Air; and this not only in a straight line, or direct, but in one bended in many angles.
Nor are the other three so perfect, but that _diligence_, _attention_, and many _mechanical contrivances_, may also highly improve them. For since the sense of _smelling_ seems to be made by the _swift passage_ of the _Air_ (_impregnated_ with the steams and _effluvia_ of several odorous Bodies) through the grisly _meanders_ of the Nose whose surfaces are _cover’d_ with a very sensible _nerve_, and _moistned_ by a _transudation_ from the _processus mamillares_ of the Brain, and some adjoyning _glandules_, and by the moist _steam_ of the _Lungs_, with a Liquor convenient for the reception of those _effluvia_ and by the adhesion and mixing of those steams with that liquor, and thereby affecting the nerve, or perhaps by insinuating themselves into the juices of the brain, after the same manner, as I have in the following Observations intimated, the parts of Salt to pass through the skins of Effs, and Frogs. Since, I say, smelling seems to be made by some such way, ’tis not improbable, but that some contrivance, for making a great quantity of Air pass quick through the Nose, might as much promote the sense of smelling, as the any wayes hindring that passage does dull and destroy it. Several tryals I have made, both of hindring and promoting this sense, and have succeeded in some according to expectation; and indeed to me it seems capable of being improv’d, for the judging of the constitutions of many Bodies. Perhaps we may thereby also judge (as other Creatures seem to do) what is wholsome, what poyson; and in a word, what are the specifick properties of Bodies.
There may be also some other mechanical wayes found out, of sensibly perceiving the _effluvia_ of Bodies; several Instances of which, were it here proper, I could give of Mineral steams and exhalations; and it seems not impossible, but that by some such wayes improved, may be discovered, what Minerals lye buried under the Earth, without the trouble to dig for them; some things to confirm this Conjecture may be found in _Agricola_, and other Writers of Minerals, speaking of the Vegetables that are apt to thrive, or pine, in those steams.
Whether also those steams, which seem to issue out of the Earth, and mix with the Air (and so to precipitate some _aqueous_ Exhalations, wherewith ’tis impregnated) may not be by some way detected before they produce the effect, seems hard to determine; yet something of this kind I am able to discover, by an Instrument I contriv’d to shew all the minute variations in the pressure of the Air; by which I constantly find, that before, and during the time of rainy weather, the pressure of the Air is less, and in _dry weather_, but especially when an _Eastern Wind_ (which having past over vast tracts of Land is heavy with Earthy Particles) blows, it is much more, though these changes are varied according to very odd Laws.
The Instrument is this. I prepare a pretty capacious Bolt-head AB, with a small stem about two foot and a half long DC; upon the end of this D I put on a small bended Glass, or brazen _syphon_ DEF (open at D, E and F, but to be closed with cement at F and E, as occasion serves) whose stem F should be about six or eight inches long, but the bore of it not above half an inch diameter, and very even; these I fix very strongly together by the help of very hard Cement, and then fit the whole Glass ABCDEF into a long Board, or Frame, in such manner, that almost half the head AB may lye buried in a concave Hemisphere cut into the Board RS; then I place it so on the Board RS, as is exprest in the first figure of the first Scheme; and fix it very firm and steady in that posture, so as that the weight of the _Mercury_ that is afterwards to be put into it, may not in the least shake or stir it; then drawing a line XY on the Frame RT, so that it may divide the ball into two equal parts, or that it may pass, as ’twere, through the center of the ball. I begin from that, and divide all the rest of the Board towards UT into inches, and the inches between the 25 and the end E (which need not be above two or three and thirty inches distant from the line XY) I subdivide into Decimals; then stopping the end F with soft Cement, or soft Wax, I invert the Frame, placing the head downwards, and the Orifice E upwards; and by it, with a small Funnel, I fill the whole Glass with Quicksilver; then by stopping the small Orifice E with my finger, I oftentimes erect and invert the whole Glass and Frame, and thereby free the Quicksilver and Glass from all the bubbles or parcels of lurking Air; then inverting it as before, I fill it top full with clear and well strain’d Quicksilver, and having made ready a small ball of pretty hard Cement, by heat made very soft, I press it into the hole E, and thereby stop it very fast; and to secure this Cement from flying out afterward, I bind over it a piece of Leather, that is spread over in the inside with Cement, and wound about it while the Cement is hot: Having thus fastned it, I gently erect again the Glass after this manner: I first let the Frame down edge-wayes, till the edge RV touch the Floor, or ly horizontal; and then in that edging posture raise the end RS; this I do, that if there chance to be any Air hidden in the small Pipe E, it may ascend into the Pipe F, and not into the Pipe DC: Having thus erected it, and hung it by the hole Q, or fixt it perpendicularly by any other means, I open the end F, and by a small _Syphon_ I draw out the _Mercury_ so long, till I find the surface of it AB in the head to touch exactly the line XY; at which time I immediately take away the _Syphon_, and if by chance it be run somewhat below the line XY, by pouring in gently a little _Mercury_ at F, I raise it again to its desired height, by this contrivance I make all the sensible rising and falling of the _Mercury_ to be visible in the surface of the _Mercury_ in the Pipe F, and scarce any in the head AB. But because there really is some small change of the upper surface also, I find by several Observations how much it rises in the Ball, and falls in the Pipe F, to make the distance between the two surfaces an inch greater then it was before; and the measure that it falls in the Pipe is the length of the inch by which I am to mark the parts of the Tube F, or the Board on which it lyes, into inches and Decimals: Having thus justned and divided it, I have a large Wheel MNOP, whose outmost limb is divided into two hundred equal parts; this by certain small Pillars is fixt on the Frame RT, in the manner exprest in the Figure. In the middle of this, on the back side, in a convenient frame, is placed a small Cylinder, whose circumference is equal to twice the length of one of those divisions, which I find answer to an inch of ascent, or descent, of _Mercury_: This Cylinder I, is movable on a very small Needle, on the end of which is fixt a very light Index KL, all which are so pois’d on the Axis, or Needle, that no part is heavier then another: Then about this Cylinder is wound a small Clew of Silk, with two small steel Bullets at each end of it GH; one of these, which is somewhat the heavier, ought to be so big, as freely to move to and fro in the Pipe F; by means of which contrivance, every the least variation of the height of the _Mercury_ will be made exceeding visible by the motion to and fro of the small Index KL.
But this is but one way of discovering the _effluvia_ of the Earth mixt with the Air; there may be perhaps many others, witness the _Hygroscope_, an Instrument whereby the watery steams volatile in the Air are discerned, which the Nose it self is not able to find. This I have describ’d in the following Tract in the Description of the Beard of a wild Oat. Others there are, may be discovered both by the Nose, and by other wayes also. Thus the _smoak_ of burning _Wood_ is _smelt_, _seen_, and sufficiently _felt_ by the eyes: The _fumes_ of burning _Brimstone_ are _smelt_ and discovered also by the destroying the Colours of Bodies, as by the _whitening of a red Rose_: And who knows, but that the Industry of man, following this method, may find out wayes of improving this sense to as great a degree of perfection at it is in any Animal, and perhaps yet higher.
’Tis not improbable also, but that our _taste_ may be very much improv’d, either by _preparing_ our taste for the Body, as, after eating _bitter_ things, _Wine_, or other _Vinous liquors_, are more sensibly tasted; or else by _preparing_ Bodies for our tast; as the dissolving of Metals with acid Liquors, make them tastable, which were before altogether insipid; thus _Lead_ becomes _sweeter_ then Sugar, and _Silver_ more _bitter_ then Gall, _Copper_ and _Iron_ of most _loathsome_ tasts. And indeed the business of this sense being to discover the presence of dissolved Bodies in Liquors put on the Tongue, or in general to discover that a fluid body has some solid body dissolv’d in it, and what they are; whatever contrivance makes this discovery improves this sense. In this kind the mixtures of Chymical Liquors afford many Instances; as the sweet Vinegar that is impregnated with Lead may be discovered to be so by the affusion of a little of an _Alcalizate solution_: The bitter liquor of _Aqua fortis_ and _Silver_ may be discover’d to be charg’d with that Metal, by laying in it some plates of Copper: ’Tis not improbable also, but there may be multitudes of other wayes of discovering the parts dissolv’d, or dissoluble in liquors; and what is this discovery but a kind of _secundary tasting_.
’Tis not improbable also, but that the sense of _feeling_ may be highly improv’d, for that being a sense that judges of the more _gross_ and _robust motions_ of the _Particles_ of _Bodies_, seems capable of being improv’d and assisted very many wayes. Thus for the distinguishing of _Heat_ and _Cold_, the _Weather-glass_ and _Thermometer_, which I have describ’d in this following Treatise, do exceedingly perfect it; by each of which the least variations of heat or cold, which the most Acute sense is not able to distinguish, are manifested. This is oftentimes further promoted also by the help of _Burning-glasses_, and the like, which collect and unite the radiating heat. Thus the _roughness_ and _smoothness_ of a Body is made much more sensible by the help of a _Microscope_, then by the most _tender_ and _delicate Hand_. Perhaps, a Physitian might, by several other _tangible_ proprieties, discover the constitution of a Body as well as by the _Pulse_. I do but instance in these, to shew what possibility there may be of many others, and what probability and hopes there were of finding them, if this method were followed; for the Offices of the five Senses being to detect either the _subtil_ and _curious Motions_ propagated through all _pellucid_ or perfectly _homogeneous_ Bodies; Or the more _gross_ and _vibrative Pulse_ communicated through the _Air_ and all other convenient _mediums_, whether fluid or solid: Or the _effluvia_ of Bodies _dissolv’d_ in the _Air_; Or the _particles_ of bodies _dissolv’d_ or _dissoluble_ in _Liquors_, or the more _quick_ and _violent shaking motion_ of _heat_ in all or any of these: whatsoever does any wayes promote any of these kinds of _criteria_, does afford a way of improving some one sense. And what a multitude of these would a diligent Man meet with in his inquiries? And this for the helping and promoting the _sensitive faculty_ only.
Next, as for the _Memory_, or _retentive faculty_, we may be sufficiently instructed from the _written Histories_ of _civil actions_, what great assistance may be afforded the Memory, in the committing to writing things observable in _natural operations_. If a Physitian be therefore accounted the more able in his Faculty, because he has had long experience and practice, the remembrance of which, though perhaps very imperfect, does regulate all his after actions: What ought to be thought of that man, that has not only a perfect _register_ of his own experience, but is grown _old_ with the experience of many hundreds of years, and many thousands of men.
And though of late, men, beginning to be sensible of this convenience, have here and there registred and printed some few _Centuries_, yet for the most part they are set down very lamely and imperfectly, and, I fear, many times not so truly, they seeming, several of them, to be design’d more for _Ostentation_ then _publique use_: For, not to instance, that they do, for the most part, omit those Experiences they have made, wherein their Patients have miscarried, it is very easie to be perceiv’d, that they do all along _hyperbolically extol_ their own Prescriptions, and vilifie those of others. Notwithstanding all which, these kinds of Histories are generally esteem’d useful, even to the ablest Physitian.
What may not be expected from the _rational_ or _deductive Faculty_ that is furnisht with such _Materials_, and those so readily _adapted_, and rang’d for use, that in a moment, as ’twere, thousands of Instances, serving for the _illustration_, _determination_, or _invention_, of almost any inquiry, may be _represented_ even to the sight? How neer the nature of _Axioms_ must all those _Propositions_ be which are examin’d before so many _Witnesses_? And how difficult will it be for any, though never so subtil an error in Philosophy, to _scape_ from being discover’d, after it has indur’d the _touch_, and so many other _tryals_?
What kind of mechanical way, and physical invention also is there requir’d that might not this way be found out? The _Invention_ of a way to find the _Longitude_ of places is easily perform’d, and that to as great _perfection_ as is desir’d, or to at great an _accurateness_ as the _Latitude_ of places can be found at Sea; and perhaps yet also to a greater certainty then that has been hitherto found, as I shall very speedily freely manifest to the world. The way of _flying_ in the Air seems principally unpracticable, by reason of the _want of strength_ in _humane muscles_; if therefore that could be suppli’d, it were, I think, easie to make twenty contrivances to perform the office of _Wings_: What Attempts also I have made for the supplying that Defect, and my successes therein, which, I think, are wholly new, and not inconsiderable, I shall in another place relate.
’Tis not unlikely also, but that _Chymists_, if they followed this method, might find out their so much sought for _Alkahest_. What an _universal Menstruum_, which dissolves all sorts of _Sulphureous Bodies_, I have discover’d (which has not been before taken notice of as such) I have shewn in the sixteenth Observation.
What a prodigious variety of Inventions in _Anatomy_ has this latter Age afforded, even in our own Bodies in the very _Heart_, by which we live, and the Brain, which is the seat of our knowledge of other things? witness all the excellent Works of _Pecquet_, _Bartholinus_, _Billius_, and many others; and at home, of Doctor _Harvy_, Doctor _Ent_, Doctor _Willis_, Doctor _Glisson_. In _Celestial Observations_ we have far exceeded all the Antients, even the _Chaldeans_ and _Egyptians_ themselves, whose _vast Plains_, _high Towers_, and _clear Air_, did not give them so great advantages over us, as have over them by our _Glasses_. By the help of which, they have been very much outdone by the famous _Galileo_, _Hevelius_, _Zulichem_; and our own Countrymen, Mr. _Rook_, Doctor _Wren_, and the great Ornament of our Church and Nation, the _Lord Bishop of Exeter_. And to say no more in _Aerial Discoveries_, there has been a wonderful progress made by the _Noble Engine_ of _the most Illustrious Mr. Boyle_, whom it becomes me to mention with all honour, not only as my particular Patron, but as the _Patron_ of _Philosophy_ it self; which he every day _increases_ by his _Labours_, and _adorns_ by his _Example_.
The good success of all these _great Men_, and many others, and the now seemingly great _obviousness_ of most of their and divers other Inventions, which from the beginning of the world have been, as ’twere, trod on, and yet not minded till these last _inquisitive_ Ages (an Argument that there may be yet behind multitudes of the like) puts me in mind to recommend such Studies, and the prosecution of them by such methods, to the _Gentlemen_ of our Nation, whose _leisure_ makes them fit to _undertake_, and the _plenty_ of their fortunes _to accomplish_, extraordinary things in this way. And I do not only propose this kind of _Experimental Philosophy_ as a matter of high _rapture_ and _delight_ of the mind, but even as a _material_ and _sensible Pleasure_. So vast it the _variety of Objects_ which will come under their Inspections, so many _different wayes_ there are _of handling_ them, so great is the _satisfaction_ of _finding_ out _new things_, that I dare compare the _contentment_ which they will injoy, not only to that of _contemplation_, but even to that which most men prefer of _the very Senses themselves_.
And if they will please to take any incouragement from so mean and so imperfect endeavours as mine, upon my own experience, I can assure them, without arrogance, That there has not been any inquiry or Problem in _Mechanicks_, that I have hitherto propounded to my self, but by a certain method (which I may on some other opportunity explain) I have been able presently to examine the possibility of it; and if so, as easily to excogitate divers wayes of performing it: And indeed it is possible to do as much by _this method_ in _Mechanicks_, as by _Algebra_ can be perform’d in _Geometry_. Nor can I at all doubt, but that the same method is as applicable to _Physical Enquiries_, and as likely to find and reap thence as plentiful a crop of Inventions; and indeed there seems to be no subject so barren, but may with this good husbandry be highly improv’d.
Toward the prosecution of this method in _Physical Inquiries_, I have here and there _gleaned_ up an _handful_ of Observations, in the collection of most of which I made use of _Microscopes_, and some other _Glasses_ and _Instruments_ that improve the sense; which way I have herein taken, not that there are not multitudes of useful and pleasant Observables, yet uncollected, obvious enough without the helps of Art, but only to promote the use of Mechanical helps for the Senses, both in the surveying the already visible World, and for the discovery of many others hitherto unknown, and to make us, with the great Conqueror, to be affected that we have not yet overcome one World when there are so many others to be discovered, every considerable improvement of _Telescopes_ or _Microscopes_ producing new Worlds and _Terra-Incognita’s_ to our view.
The Glasses I used were of our English make, but though very good of the kind, yet far short of what might be expected, could we once find a way of making Glasses Elliptical, or of some more true shape; for though both _Microscopes_, and _Telescopes_, as they now are, will magnifie an Object about a thousand thousand times bigger then it appears to the naked eye; yet the Apertures of the Object glasses are so very small, that very few Rays are admitted, and even of those few there are so many false, that the Object appears _dark_ and _indistinct_: And indeed these inconveniences are such, as seem inseparable from Spherical Glasses, even when most exactly made; but the way we have hitherto made use of for that purpose is so imperfect, that there may be perhaps ten wrought before one be made tolerably good, and most of those ten perhaps every one differing in goodness one from another, which is an Argument, that the way hitherto used is, at least, very uncertain. So that these Glasses have a double defect; the one, that very few of them are exactly true wrought; the other, that even of those that are best among them, none will admit a sufficient number of Rayes to magnifie the Object beyond a determinate bigness. Against which Inconveniences the only Remedies I have hitherto met with are these.
First, for _Microscopes_ (where the Object we view is near and within our power) the best way of making it appear bright in the Glass, is to cast a great quantity of light on it by means of _convex glasses_, for thereby, though the aperture be very small, yet there will throng in through it such multitudes, that an Object will by this means indure to be magnifi’d as much again as it would be without it. The way for doing which is this. I make choice of some Room that has only one window open to the South, and at about three or four foot distance from this Window, on a Table, I place my _Microscope_, and then so place either a round Globe of Water, or a very deep clear_ plano convex_ Glass (whose convex side is turn’d towards the Window) that there is a great quantity of Rayes collected and thrown upon the Object: Or if the Sun shine, I place a small piece of oyly Paper very near the Object, between that and the light; then with a good large Burning-Glass I so collect and throw the Rayes on the Paper, that there may be a very great quantity of light pass through it to the Object; yet I so proportion that light, that it may not singe or burn the Paper. Instead of which Paper there may be made use of a small piece of Looking-glass plate, one of whose sides is made rough by being rubb’d on a flat Tool with very fine sand, this will, if the heat be leisurely cast on it, indure a much greater degree of heat, and consequently very much augment a convenient light. By all which means the light of the Sun, or of a Window, may be so cast on an Object, as to make it twice as light as it would otherwise be without it, and that without any inconvenience of glaring, which the immediate light of the Sun is very apt to create in most Objects; for by this means the light is so equally diffused, that all parts are alike inlightned; but when the immediate light of the Sun falls on it, the reflexions from some few parts are so vivid, that they drown the appearance of all the other, and are themselves also, by reason of the inequality of light, indistinct, and appear only radiant spots.
But because the light of the Sun, and also that of a Window, is in a continual variation, and so many Objects cannot be view’d long enough by them to be throughly examin’d; besides that, oftentimes the Weather is so dark and cloudy, that for many dayes together nothing can be view’d: And because also there are many Objects to be met with in the night, which cannot so conveniently be kept perhaps till the day, therefore to procure and cast a sufficient quantity of light on an Object in the night, I thought of, and often used this, Expedient.
I procur’d me a small Pedestal, such as is describ’d in the fifth Figure of the first _Scheme_ on the small Pillar AB, of which were two movable Armes CD, which by means of the Screws EF, I could fix in any part of the Pillar; on the undermost of these I plac’d a pretty large Globe of Glass G, fill’d with exceeding clear Brine, stopt, inverted, and fixt in the manner visible in the Figure; out of the side of which Arm proceeded another Arm H, with many joynts; to the end of which was fastned a deep plain _Convex glass_ I, which by means of this Arm could be moved to and fro, and fixt in any posture. On the upper Arm was placed a small Lamp K, which could be so mov’d upon the end of the Arm, as to be set in a fit posture to give light through the Ball: By means of this Instrument duly plac’d, as is exprest in the Figure, with the small flame of a Lamp may be cast as great and convenient a light on the Object as it will well indure; and being always constant, and to be had at any time, I found most proper for drawing the representations of those small Objects I had occasion to observe.
None of all which ways (though much beyond any other hitherto made use of by any I know) do afford a sufficient help, but after a certain degree of magnifying, they leave us again in the lurch. Hence it were very desirable, that some way were thought of for making the Object-glass of such a Figure as would conveniently bear a large Aperture.
As for _Telescopes_, the only improvement they seem capable of, is the increasing of their length; for the Object being remote, there is no thought of giving it a greater light then it has; and therefore to augment the Aperture, the Glass must be ground of a very large sphere; for, by that means, the longer the Glass be, the bigger aperture will it bear, if the Glasses be of an equal goodness in their kind. Therefore a six will indure a much larger Aperture then a three foot Glass, and a sixty foot Glass will proportionably bear a greater Aperture then a thirty, and will as much excel it also as a six foot does a three foot, as I have experimentally observ’d in one of that length made by Mr. _Richard Reives_ here at _London_, which will bear an Aperture above three inches over, and yet make the Object proportionably big and distinct; whereas there are very few thirty foot Glasses that will indure an Aperture of more then two inches over. So that for _Telescopes_, supposing we had a very ready way of making their Object Glasses of exactly spherical Surfaces, we might, by increasing the length of the Glass, magnifie the Object to any assignable bigness. And for performing both these, I cannot imagine any way more easie, and more exact, then by this following Engine, by means of which, any Glasses, of what length soever, may be speedily made. It seems the most easie, because with one and the same Tool may be with care ground an Object Glass, of any length or breadth requisite, and that with very little or no trouble in fitting the Engine, and without much skill in the Grinder. It seems to be the most exact, for to the very last stroke the Glass does regulate and rectifie the Tool to its exact Figure; and the longer or more the Tool and Glass are wrought together, the more exact will both of them be of the desir’d Figure. Further, the motions of the Glass and Tool do so cross each other, that there is not one point of eithers Surface, but has thousands of cross motions thwarting it, so that there can be no kind of Rings or Gutters made either in the Tool or Glass.
The contrivance of the Engine is, only to make the ends of two large _Mandrils_ so to move, that the Centers of them may be at any convenient distance asunder, and that the _Axis_ of the _Mandrils_ lying both in the same plain produc’d, may meet each other in any assignable Angle; both which requisites may be very well perform’d by the Engine describ’d in the third Figure of the first _Scheme_: where AB signifies the Beam of a Lath fixt perpendicularly or Horizontally, CD the two Poppet heads, fixt at about two foot distance, EF an Iron _Mandril_, whose tapering neck F runs in an adapted tapering brass Collar; the other end E runs on the point of a Screw G; in a convenient place of this is fastned H a pully Wheel, and into the end of it, that comes through the Poppet head C, is screwed a Ring of a hollow _Cylinder_ K, or some other conveniently shap’d Tool, of what wideness shall be thought most proper for the cize of Glasses, about which it is to be imploy’d: As, for Object glasses, between twelve foot and an hundred foot long, the Ring may be about six inches over, or indeed somewhat more for those longer Glasses. It would be convenient also, and not very chargeable, to have four or five several Tools; as one for all Glasses between an inch and a foot, one for all Glasses between a foot and ten foot long, another for all between ten and an hundred, a fourth for all between a hundred and a thousand foot long; and if Curiosity shall ever proceed so far, one for all lengths between a thousand and ten thousand foot long; for indeed the principle is such, that supposing the _Mandrils_ well made, and of a good length, and supposing great care be used in working and polishing them, I see no reason, but that a Glass of a thousand, nay of ten thousand foot long, may be as well made as one of ten; for the reason is the same, supposing the _Mandrils_ and Tools be made sufficiently strong, so that they cannot bend; and supposing the Glass, out of which they are wrought, be capable of so great a regularity in its parts as to refraction: this hollow _Cylinder_ K is to contain the Sand, and by being drove round very quick to and fro by means of a small Wheel, which may be mov’d with ones foot, serves to grind the Glass: The other _Mandril_ is shap’d like this, but it has an even neck instead of a taper one, and runs in a Collar, that by the help of a Screw and a joynt made like M in the Figure, it can be still adjustned to the wearing or wasting neck: into the end of this _Mandril_ is screwed a Chock N on which with Cement or Glew is fastned the piece of Glass Q that is to be form’d; the middle of which Glass is to be plac’d just on the edge of the Ring, and the Lath OP is to be set and fixt (by means of certain pieces and screws, the manner whereof will be sufficiently evidenc’d by the Figure) in such an Angle as is requisite to the forming of such a Sphere as the Glass is design’d to be of; the geometrical ground of which being sufficiently plain, though not heeded before, I shall, for brevities sake, pass over. This last _Mandril_ to be made (by means of the former, or some other Wheel) to run round very swift also, by which two cross motions the Glass cannot chuse (if care be us’d) but be wrought into a most exactly spherical Surface.
But because we are certain, from the _Laws of refraction_ (which I I have experimentally found to be so, by an Instrument I shall presently describe) that _the lines of the angles of Incidence are proportionate to the lines of the angles of Refraction_, therefore if Glasses could be made of those kind of Figures, or some other, such as the most incomparable _Des Cartes_ has invented, and demonstrated in his Philosophical and Mathematical Works, we might hope for a much greater perfection of Opticks then can be rationally expected from spherical ones; for though, _cæteris paribus_, we find, that the larger the _Telescope_ Object Glasses are, and the shorter those of the _Microscope_, the better they magnifie, yet both of them, beside such determinate dimensions, are by certain inconveniences rendred unuseful; for it will be exceeding _difficult_ to make and _manage_ a Tube above an _hundred foot long_, and it will be as difficult to _inlighten_ an Object less then an hundred part of an inch distant from the Object Glass.
I have not as yet made any attempts of that kind, though I know two or three wayes, which, as far as I have yet considered, seem very probable, and may invite me to make a tryal as soon as I have an opportunity, of which I may hereafter perhaps acquaint the world. In the Interim, I shall describe the Instrument I even now mention’d, by which the _refraction_ of all kinds of Liquors may be most exactly measur’d, thereby to give the curious an opportunity of making what further tryals of that kind they shall think requisite to any of their intended tryals; and to let them see that the laws of Refraction are not only notional.
The Instrument consisted of five Rulers, or long pieces placed together, after the manner exprest in the second Figure of the first _Scheme_, where AB denotes a straight piece of wood about six foot and two inches long, about three inches over, and an inch and half thick, on the back side of which was hung a small plummet by a line stretcht from top to bottom, by which this piece was set exactly upright, and so very firmly fixt; in the middle of this was made a hole or center, into which one end of a hollow cylindrical brass Box CC, fashion’d as I shall by and by describe, was plac’d, and could very easily and truly be mov’d to and fro; the other end of this Box being put into, and moving in, a hole made in a small arm DD; into this box was fastned the long Ruler EF, about three foot and three or four inches long, and at three foot from the above mention’d Centers PP was a hole E, cut through, and cross’d with two small threads, and at the end of it was fixt a small sight G, and on the back side of it was fixt a small Arm H, with a Screw to fix it in any place on the Ruler LM; this Ruler LM was mov’d on the Center B (which was exactly three foot distance from the middle Center P) and a line drawn through the middle of it LM, was divided by a Line of cords into some sixty degrees, and each degree was subdivided into minutes, so that putting the cross of the threads in E upon any part of this divided line, I presently knew what Angle the two Rules AB and EF made with each other, and by turning the Screw in H, I could fix them in any position. The other Ruler also RS was made much after the same manner, only it was not fixt to the hollow cylindrical Box, but, by means of two small brass Armes or Ears, it mov’d on the Centers of it; this also, by means of the cross threads in the hole S, and by a Screw in K, could be fastned on any division of another line of cords of the same radius drawn on NO. And so by that means, the Angle made by the two Rulers, AB and RS, was also known. The Brass box CC in the middle was shap’d very much like the Figure X, that is, it was a cylindrical Box stopp’d close at either end, off of which a part both of the sides and bottomes was cut out, so that the Box, when the Pipe and that was joyned to it, would contain the Water when fill’d half full, and would likewise, without running over, indure to be inclin’d to an Angle, equal to that of the greatest refraction of Water, and no more, without running over. The Ruler EF was fixt very fast to the Pipe V, so that the Pipe V directed the length of the Ruler EF, and the Box and Ruler were mov’d on the Pin TT, so as to make any desirable Angle with the Ruler AB. The bottom of this Pipe V was stop’d with a small piece of exactly plain Glass, which was plac’d exactly perpendicular to the Line of direction, or _Axis_ of the Ruler EF. The Pins also TT were drill’d with small holes through the _Axis_, and through those holes was stretcht and fastned a small Wire. There was likewise a small Pipe of Tin loosly put on upon the end of V, and reaching down to the sight G; the use of which was only to keep any false Rayes of light from passing through the bottom of V, and only admitting such to pass as pierced through the sight G: All things being placed together in the manner describ’d in the Figure; that is, the Ruler AB being fixt perpendicular, I fill’d the Box CC with Water, or any other Liquor, whose refraction I intended to try, till the Wire passing through the middle of it were just covered: then I moved and fixt the Ruler FE at any assignable Angle, and placed the flame of a Candle just against the sight G; and looking through the sight I, I moved the Ruler RS to and fro, till I perceived the light passing through G to be covered, as ’twere, or divided by the dark Wire passing through PP: then turning the Screw in K, I fixt it in that posture: And through the hole S, I observed what degree and part of it was cut by the cross threads in S. And this gave me the Angle of Inclination, APS answering to the Angle of Refraction BPE: for the surface of the Liquor in the Box will be alwayes horizontal, and consequently AB will be a perpendicular to it; the Angle therefore APS will measure, or be the Angle of Inclination in the Liquor; next EPB must be the Angle of Refraction, for the Ray that passes through the sight G, passes also perpendicularly through the Glass _Diaphragme_ at F, and consequently also perpendicularly through the lower surface of the Liquor contiguous to the Glass, and therefore suffers no refraction till it meet with the horizontal surface of the Liquor in CC, which is determined by the two Angles.
By means of this Instrument I can with _little trouble_, and a very small quantity of any _Liquor_, examine, most accurately, the _refraction_ of it not only for one inclination, but for all; and thereby am inabled to make very accurate Tables; several of which I have also experimentally made, and find, that _Oyl of Turpentine_ has a much greater Refraction then _Spirit of Wine_, though it be _lighter_; and that _Spirit of Wine_ has a greater Refraction then _Water_, though it be lighter also; but that _salt Water_ also has a greater Refraction then _fresh_, though it be _heavier_: but _Alum water_ has a less refraction then common _Water_, though heavier also. So that it seems, as to the _refraction_ made in a Liquor, the _specifick gravity_ is of no efficacy. By this I have also found that look what _proportion _the _Sine_ of the Angle of _one Inclination_ has to the _Sine_ of the Angle of _Refraction_, correspondent to it, the same _proportion_ have all the _Sines_ of other Inclinations to the _Sines_ of their appropriate Refractions.
My way for measuring how much a Glass magnifies an Object, plac’d at a convenient distance from my eye, is this. Having rectifi’d the _Microscope_, to see the desir’d Object through it very distinctly, at the same time that I look upon the Object through the Glass with one eye, I look upon other Objects at the same distance with my other bare eye; by which means I am able, by the help of a _Ruler_ divided into inches and small parts, and laid on the _Pedestal_ of the _Microscope_, to cast, as it were, the magnifi’d appearance of the Object upon the Ruler, and thereby exactly to measure the Diameter it appears of through the Glass, which being compar’d with the Diameter it appears of to the naked eye, will easily afford the quantity of its magnifying.
The _Microscope_, which for the most part I made use of, was shap’d much like that in the sixth Figure of the first _Scheme_, the Tube being for the most part not above six or seven inches long, though, by reason it had four Drawers, it could very much be lengthened, as occasion required; this was contriv’d with three Glasses; a small Object Glass at A, a thinner Eye Glass about B, and a very deep one about C: this I made use of only when I had occasion to see much of an Object at once; the middle Glass conveying a very great company of radiating Pencils, which would go another way, and throwing them upon the deep Eye Glass. But when ever I had occasion to examine the small parts of a Body more accurately, I took out the middle Glass, and only made use of one Eye Glass with the Object Glass, for always the fewer the Refractions are, the more bright and clear the Object appears. And therefore ’tis not to be doubted, but could we make a_ Microscope _to have one only refraction, it would, _cæteris paribus_, far excel any other that had a greater number. And hence it is, that if you take a very clear piece of a broken _Venice_ Glass, and in a Lamp draw it out into very small hairs or threads, then holding the ends of these threads in the flame, till they melt and run into a small round Globul, or drop, which will hang at the end of the thread; and if further you stick several of these upon the end of a stick with a little sealing Wax, so as that the threads stand upwards, and then on a Whetstone first grind off a good part of them, and afterward on a smooth Metal plate, with a little Tripoly, rub them till they come to be very smooth; if one of these be fixt with a little soft Wax against a small needle hole, prick’d through a thin Plate of Brass, Lead, Pewter, or any other Metal, and an Object, plac’d very near, be look’d at through it, it will both magnifie and make some Objects more distinct then any of the great _Microscopes_. But because these, though exceeding easily made, are yet very troublesome to be us’d, because of their smalness, and the nearness of the Object; therefore to prevent both these, and yet have only two Refractions, I provided me a Tube of Brass, shap’d much like that in the fourth Figure of the first _Scheme_; into the smaller end of this I fixt with Wax a good _plano convex_ Object Glass, with the convex side towards the Object, and into the bigger end I fixt also with wax a pretty large plano _Convex_ Glass, with the _convex_ side towards my eye, then by means of the small hole by the side, I fill’d the intermediate space between these two Glasses with very clear Water, and with a Screw stopp’d it in; then putting on a Cell for the Eye, I could perceive an Object more bright then I could when the intermediate space was only fill’d with Air, but this, for other inconveniences, I made but little use of.
My way for fixing both the Glass and Object to the Pedestal most conveniently was thus: Upon one side of a round Pedestal AB, in the sixth Figure of the first _Scheme_, was fixt a small Pillar CC, on this was fitted a small Iron Arm D, which could be mov’d up and down, and fixt in any part of the Pillar, by means of a small Screw E; on the end of this Arm was a small Ball fitted into a kind of socket F, made in the side of the Brass Ring G, through which the small end of the Tube was screw’d; by means of which contrivance I could place and fix the Tube in what posture I desir’d (which for many Observations was exceeding necessary) and adjusten it most exactly to any Object.
For placing the Object, I made this contrivance; upon the end of a small brass Link or Staple HH, I so fastned a round Plate II, that it might be turn’d round upon its Center K, and going pretty stiff, would stand fixt in any posture it was set; on the side of this was fixt a small Pillar P, about three quarters of an inch high, and through the top of this was thrust a small Iron pin M, whose top just stood over the Center of the Plate; on this top I fixt a small Object, and by means of these contrivances I was able to turn it into all kind of positions, both to my Eye and the Light; for by moving round the small Plate on its center, could move it one way, and by turning the Pin M, I could move it another way, and this without stirring the Glass at all, or at least but very little; the Plate likewise I could move to and fro to any part of the Pedestal (which in many cases was very convenient) and fix it also in any Position, by means of a Nut N, which was screw’d on upon the lower part of the Pillar CC. All the other Contrivances are obvious enough from the draught, and will need no description.
Now though this were the Instrument I made most use of, yet I have made several other Tryals with other kinds of Microscopes, which both for _matter_ and _form_ were very different from common spherical Glasses. I have made a _Microscope_ with one piece of Glass, both whose surfaces were _plains_. I have made another only with a _plano concave_, without any kind of reflection, divers also by means of _reflection_. I have made others of _Waters_, _Gums_, _Resins_, _Salts_, _Arsenick_, _Oyls_, and with divers other _mixtures of watery_ and _oyly Liquors_. And indeed the subject is capable of a great variety; but I find generally none more useful then that which is made with _two Glasses_, such as I have already describ’d.
What the things are I observ’d, the following descriptions will manifest; in brief, they were either _exceeding small Bodies_, or _exceeding small Pores_, or _exceeding small Motions_, some of each of which the Reader will find in the following Notes, and such, as I presume, (many of them at least) will be _new_, and perhaps not less _strange_: Some _specimen_ of each of which Heads the Reader will find in the subsequent delineations, and indeed of some more then I was willing there should be; which was occasioned by my first Intentions to print a much greater number then I have since found time to compleat. Of such therefore as I had, I selected only some few of every Head, which for some particulars seem’d most observable, rejecting the rest as superfluous to the present Design.
What each of the delineated Subjects are, the following descriptions annext to each will inform, of which I shall here, only once for all, add, That in divers of them the Gravers have pretty well follow’d my directions and draughts; and that in making of them, I indeavoured (as far as I was able) first to discover the true appearance, and next to make a plain representation of it. This I mention the rather, because of these kind of Objects there is much more difficulty to discover the true shape, then of those visible to the naked eye, the same Object seeming quite differing, in one position to the Light, from what it really is, and may be discover’d in another. And therefore I never began to make any draught before by many examinations in several lights, and in several positions to those lights, I had discover’d the true form. For it is exceeding difficult in some Objects, to distinguish between a _prominency_ and a _depression_, between a _shadow_ and a _black stain_, or a _reflection_ and a _whiteness in the colour_. Besides, the transparency of most Objects renders them yet much more difficult then if they were _opacous_. The Eyes of a Fly in one kind of light appear almost like a Lattice, drill’d through with abundance of small holes; which probably may be the Reason, why the Ingenious _Dr. Power_ seems to suppose them such. In the Sunshine they look like a Surface cover’d with golden Nails; in another posture, like a Surface cover’d with Pyramids; in another with Cones; and in other postures of quite other shapes; but that which exhibits the best, is the Light collected on the Object, by those means I have already describ’d.
And this was undertaken in prosecution of the Design which the _ROYAL SOCIETY_ has propos’d to it self. For the Members of the Assembly having before their eys so many _fatal_ Instances of the errors and falshoods, in which the greatest part of mankind has so long wandred, because they rely’d upon the strength of humane Reason alone, have begun anew to correct all _Hypotheses_ by sense, as Seamen do their _dead Reckonings_ by _Cœlestial Observations_; and to this purpose it has been their principal indeavour to _enlarge & strengthen_ the _Senses_ by _Medicine_, and by such _outward Instruments_ as are proper for their particular works. By this means they find some reason to suspect, that those effects of Bodies, which have been commonly attributed to _Qualities_, and those confess’d to be _occult_, are perform’d by the small _Machines_ of Nature, which are not to be discern’d without these helps, seeming the meer products of _Motion_, _Figure_, and _Magnitude_; and that the _Natural Textures_, which some call the _Plastick faculty_, may be made in _Looms_, which a greater perfection of Opticks may make discernable by these Glasses; so as now they are no more puzzled about them, then the vulgar are to conceive, how _Tapestry_ or _flowred Stuffs_ are woven. And the ends of all these Inquiries they intend to be the _Pleasure_ of Contemplative minds, but above all, the _ease and dispatch_ of the labours of mens hands. They do indeed neglect no opportunity to bring all the _rare_ things of Remote Countries within the compass of their knowledge and practice. But they still acknowledg their _most useful_ Informations to arise from _common_ things, and from _diversifying_ their most _ordinary_ operations upon them. They do not wholly reject Experiments of meer _light_ and _theory_; but they principally aim at such, whose Applications will _improve and facilitate_ the present way of _Manual Arts_. And though some men, who are perhaps taken up about less honourable Employments, are pleas’d to censure their proceedings, yet they can shew more _fruits_ of their first three years, wherein they have assembled, then any other _Society_ in _Europe_ can for a much larger space of time. ’Tis true, such undertakings as theirs do commonly meet with small incouragement, because men are generally rather taken with the _plausible_ and _discursive_, then the _real_ and the solid part of Philosophy; yet by the good fortune of their institution, in an Age of all others the most _inquisitive_, they have been assisted by the _contribution_ and _presence_ of very many of the chief _Nobility_ and _Gentry_, and others who are some of the _most considerable_ in their several Professions. But that that yet farther convinces me of the _Real esteem_ that the more _serious_ part of men have of this _Society_, is, that several _Merchants_, men who act in earnest (whose Object is _meum & tuum_, that great _Rudder_ of humane affairs) have adventur’d considerable sums of _Money_, to put in practice what some of our Members have contrived, and have continued _stedfast_ in their good opinions of such Indeavours, when not one of a hundred of the vulgar have believed their undertakings feasable. And it is also fit to be added, that they have one advantage peculiar to themselves, that very many of their number are _men of Converse and Traffick_; which is a good Omen, that their attempts will bring Philosophy from _words_ to _action_, seeing the men of Business have had so great a share in their first foundation.
And of this kind I ought not to conceal one particular _Generosity_, which more nearly concerns my self. It is the _munificence_ of _Sir John Cutler_, in endowing a Lecture for the promotion of _Mechanick Arts_, to be governed and directed by This _Society._This _Bounty_ I mention for the _Honourableness_ of the thing it self, and for the expectation which I have of the _efficacy_ of the _Example_; for it cannot now be objected to them, that their Designs will be esteemed _frivolous_ and _vain_, when they have such a _real Testimony_ of the _Approbation_ of a _Man_ that is such an _eminent Ornament_ of this renowned City, and one, who, by the _Variety_, and the _happy Success_, of his negotiations, has given evident proofs, that he is not easie to be deceiv’d. This Gentleman has well observ’d, that the _Arts_ of life have been too long _imprison’d_ in the dark shops of Mechanicks themselves, & there _hindred from growth_, either by ignorance, or self-interest: and he has bravely _freed_ them from these _inconveniences_: He hath not only obliged _Tradesmen_, but _Trade_ it self: He has done a work that is worthy of _London_, and has taught the chief City of Commerce in the world the right way how Commerce is to be improv’d. We have already seen many other great signs of Liberality and a large mind, from the same hand: For by his _diligence_ about the _Corporation for the Poor_; by his honorable _Subscriptions_ for the rebuilding of St. Paul’s; by his chearful _Disbursment_ for the replanting of _Ireland_, and by many other such _publick works_, he has shewn by what means he indeavours to _establish_ his Memory; and now by this last gift he has done that, which became one of the _wisest Citizens_ of our Nation to accomplish, seeing one of the _wisest of our Statesmen, the Lord Verulam_, first propounded it.
But to return to my Subject, from a digression, which, I hope, my Reader will pardon me, seeing the Example is so rare that I can make no more such digressions. If these my first Labours shall be any wayes useful to inquiring men, I must attribute the incouragement and promotion of them to a very _Reverend_ and _Learned Person_, of whom this ought in justice to be said, _That there is scarce any one Invention, which this Nation has produc’d in our Age, but it has some way or other been set forward by his assistance_. My Reader, I believe, will quickly ghess, that it is _Dr. Wilkins_ that I mean. He is indeed a man born for the _good_ of _mankind_, and for the _honour_ of his _Country_. In the _sweetness_ of whose _behaviour_, in the _calmness_ of his _mind_, in the _unbounded goodness_ of his _heart_, we have an evident Instance, what the true and the _primitive unpassionate Religion_ was, before it was _sowred_ by particular _Factions._ In a word, his _Zeal_ has been so _constant_ and _effectual_ in advancing all good and profitable _Arts, that_ as one of the Antient _Romans_ said of _Scipio_, _That he thanked God that he was a _Roman_; because whereever _Scipio_ had been born, there had been the seat of the Empire of the world_: So may I thank God, that _Dr. Wilkins_ was an _Englishman_, for whereever he had lived, there had been the chief Seat of _generous Knowledge_ and _true Philosophy_. To the truth of this, there are so many worthy men living that will subscribe, that I am confident, what I have here said, will not be looked upon, by any ingenious Reader, as a _Panegyrick_, but only as a _real testimony_.
By the Advice of this _Excellent man_ I first set upon this Enterprise, yet still came to it with much _Reluctancy_, because I was to follow the footsteps of so eminent a Person as _Dr. Wren_, who was the first that attempted any thing of this nature; whose original draughts do now make one of the Ornaments of that great Collection of Rarities in the _Kings Closet_. This _Honor_, which his first beginnings of this kind have receiv’d, to be admitted into the most famous place of the world, did not so much _incourage_, as the _hazard_ of coming after _Dr. Wren_ did _affright_ me; for of him I must affirm, that, since the time of _Archimedes_, there scarce ever met in one man, in so great a perfection, such a _Mechanical Hand_, and so _Philosophical_ a _Mind_.
But at last, being assured both by _Dr. Wilkins_, and _Dr. Wren_ himself, that he had given over his intentions of prosecuting it, and not finding that there was any else design’d the pursuing of it, I set upon this undertaking, and was not a little incourag’d to proceed in it, by the Honour the _Royal Society_ was pleas’d to favour me with, in approving of those draughts (which from time to time as I had an opportunity of describing) I presented to them. And particularly by the Incitements of divers of those Noble and excellent Persons of it, which were my more especial Friends, who were not less urgent with me for the publishing, then for the prosecution of them.
After I had almost compleated these Pictures and Observations (having had divers of them engraven, and was ready to send them to the Press) I was inform’d, that the Ingenious Physitian _Dr. Henry Power_ had made several _Microscopical_ Observations, which had I not afterwards, upon our interchangably viewing each others Papers, found that they were for the most part differing from mine, either in the Subject it self, or in the particulars taken notice of; and that his design was only to print Observations without Pictures, I had even then _suppressed_ what I had so far proceeded in. But being further _excited_ by several of my Friends, in compliance with their opinions, that it would not be unacceptable to several inquisitive Men, and hoping also, that I should thereby discover something New to the World, I have at length cast in my Mite, into the vast Treasury of _A Philosophical History_. And it is my _hope_, as well as _belief_, that these my _Labours_ will be no more comparable to the _Productions_ of many other _Natural Philosophers_, who are now every where busie about _greater_ things; then my _little Objects_ are to be compar’d to the greater and more beautiful _Works of Nature_, A Flea, a Mite, a Gnat, to an Horse, an Elephant, or a Lyon.
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