Micrographia. Robert Hooke
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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 smallness, and the nearness of the Object; therefore to prevent both these, and yet have only two Refractions, I Schem. 1. Fig. 4. 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.
Schem. 1. Fig. 3.
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