Micrographia — Preface (part 2)

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.

* * * * * MICROGRAPHIA,

OR SOME

Physiological Descriptions OF

MINUTE BODIES,

MADE BY

MAGNIFYING GLASSES;

WITH

OBSERVATIONS and INQUIRIES thereupon.