Micrographia 14That they were all, as farr as I was able to find, solid Cylindrical (part 1)
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Literature · Science
Micrographia 14
That they were all, as farr as I was able to find, solid Cylindrical (part 1)
HookeEnglish
bodies, not pervious, like a Cane or Bulrush; nor could I find that they had any Pith, or distinction of Rind, or the like, such as I had observ’d in Horse-hairs, the Bristles of a Cat, the Indian Deer’s Hair, &c.
Observations on several other sorts of Hair.
For the Brisles of a Hogg, I found them to be first a hard transparent horny substance, without the least appearance of pores or holes in it; and this I try’d with the greatest care I was able, cutting many of them with a very sharp Razor, so that they appear’d, even in the Glass, to have a pretty smooth surface, but somewhat waved by the sawing to and fro of the Razor, as is visible in the end of the Prismatical body A of the same Figure; and then making trials with causing the light to be cast on them all the various ways I could think of, that was likely to make the pores appear, if there had been any, I was not able to discover any.
Next, the Figure of the Brisles was very various, neither perfectly round, nor sharp edg’d, but Prismatical, with divers sides, and round angles, as appears in the Figure A. The bending of them in any part where they before appear’d cleer, would all flaw them, and make them look white.
The Mustacheos of a Cat (part of one of which is represented by the short Cylinder B of the same Figure) seem’d to have, all of them that I observ’d, a large pith in the middle, like the pith of an Elder, whose texture was so close, that I was not able to discover the least sign of pores; and those parts which seem to be pores, as they appear’d in one position to the light, in another I could find a manifest reflection to be cast from them.
This I instance in, to hint that it is not safe to conclude any thing to be positively this or that, though it appear never so plain and likely when look’d on with a Microscope in one posture, before the same be examin’d by placing it in several other positions.
And this I take to be the reason why many have believed and asserted the Hairs of a man’s head to be hollow, and like so many small pipes perforated from end to end.
Now, though I grant that by an Analogie one may suppose them so, and from the Polonian disease one may believe them such, yet I think we have not the least encouragement to either from the Microscope, much less positively to assert them such. And perhaps the very essence of the Plica Polonica may be the hairs growing hollow, and of an unnatural constitution.
And as for the Analogie, though I am apt enough to think that the hairs of several Animals may be perforated somewhat like a Cane, or at least have a kind of pith in them, first, because they seem as ’twere a kind of Vegetable growing on an Animal, which growing, they say, remains a long while after the Animal is dead, and therefore should like other Vegetables have a pith; and secondly, because Horns and Feathers, and Porcupine’s Quils, and Cats Brisles, and the long hairs of Horses, which come very neer the nature of a mans hair, seem all of them to have a kind of pith, and some of them to be porous, yet I think it not (in these cases, where we have such helps for the sense as the Microscope affords) safe concluding or building on more then we sensibly know, since we may, with examining, find that Nature does in the make of the same kind of substance, often vary her method in framing of it: Instances enough to confirm this we may find in the Horns of several creatures: as what a vast difference is there between the Horns of an Oxe, and those of some sorts of Staggs as to their shape? and even in the hairs of several creatures, we find a vast difference, as the hair of a man’s head seems, as I said before, long, Cylindrical and sometime a little Prismatical, solid or impervious, and very small; the hair of an Indian Deer (a part of the middle of which is described in the third Figure of the fifth Scheme, marked with F) is bigger in compass through all the middle of it, then the Bristle of an Hogg, but the end of it is smaller then the hair of any kind of Animal (as may be seen by the Figure G) the whole belly of it, which is about two or three Inches long, looks to the eye like a thread of course Canvass, that has been newly unwreath’d, it being all wav’d or bended to and fro, much after that manner, but through the Microscope, it appears all perforated from side to side, and Spongie, like a small kind of spongy Coral, which is often found upon the English shores; but though I cut it transversly, I could not perceive that it had any pores that ran the long way of the hair: the long hairs of Horses CC and D, seem Cylindrical and somewhat pithy; the Bristles of a Cat B, are conical and pithy: the Quils of Porcupines and Hedghoggs, being cut transversly, have a whitish pith, in the manner of a Starr, or Spur-rowel: Piggs-hair (A) is somewhat triagonal, and seems to have neither pith nor pore: And other kinds of hair have quite a differing structure and form. And therefore I think it no way agreeable to a true natural Historian, to pretend to be so sharp-sighted, as to see what a preconceiv’d Hypothesis tells them should be there, where another man, though perhaps as seeing, but not forestall’d, can discover no such matter.
But to proceed; I observ’d several kind of hairs that had been Dyed, and found them to be a kind of horny Cylinder, being of much about the transparency of a pretty cleer piece of Oxe horn; these appear’d quite throughout ting’d with the colours they exhibited. And ’tis likely, that those hairs being boyl’d or steep’d in those very hot ting’d liquors in the Dye-fat, And the substance of the hair being much like that of an Oxes Horn, the penetrant liquor does so far mollifie and soften the substance, that it sinks into the very center of it, and so the ting’d parts come to be mix’d and united with the very body of the hair, and do not (as some have thought) only stick on upon the outward surface. And this, the boiling of Horn will make more probable; for we shall find by that action, that the water will insinuate it self to a pretty depth within the surface of it, especially if this penetrancy of the water be much helped by the Salts that are usually mix’d with the Dying liquors. Now, whereas Silk may be dyed or ting’d into all kind of colours without boiling or dipping into hot liquors, I ghess the reason to be two-fold: First, because the filaments, or small cylinders of Silk, are abundantly smaller and finer, and so have a much less depth to be penetrated then most kind of hairs; and next, because the substance or matter of Silk, is much more like a Glew then the substance of Hair is. And that I have reason to suppose: First, because when it is spun or drawn out of the Worm, it is a perfect glutinous substance, and very easily sticks and cleaves to any adjacent body, as I have several times observed, both in Silk-worms and Spiders. Next, because that I find that water does easily dissolve and mollifie the substance again, which is evident from their manner of ordering those bottoms or pods of the Silk-worm before they are able to unwind them. It is no great wonder therefore, if those Dyes or ting’d liquors do very quickly mollifie and tinge the surfaces of so small and so glutinous a body. And we need not wonder that the colours appear so lovely in the one, and so dull in the other, if we view but the ting’d cylinders of both kinds with a good Microscope; for whereas the substance of Hair, at best, is but a dirty duskish white somewhat transparent, the filaments of Silk have a most lovely transparency and cleerness, the difference between those two being not much less then that between a piece of Horn, and a piece of Crystal; the one yielding a bright and vivid reflection from the concave side of the cylinder, that is, from the concave surface of the Air that incompasses the back-part of the cylinder; the other yielding a dull and perturb’d reflection from the several Heterogeneous parts that compose it. And this difference will be manifest enough to the eye, if you get a couple of small Cylinders, the smaller of Crystal Glass, the other of Horn, and then varnishing them over very thinly with some transparent colour, which will represent to the naked eye much the same kind of object which is represented to it from the filaments of Silk and Hair by the help of the Microscope. Now, since the threads of Silk and Serge are made up of a great number of these filaments, we may henceforth cease to wonder at the difference. From much the same reason proceeds the vivid and lovely colours of Feathers, wherein they very farr exceed the natural as well as Artificial colours of hair, of which I shall say more in its proper place.
The Teguments indeed of creatures are all of them adapted to the peculiar use and convenience of that Animal which they inwrap; and very much also for the ornament and beauty of it, as will be most evident to any one that shall attentively consider the various kinds of cloathings wherewith most creatures are by Nature invested and cover’d. Thus I have observed, that the hair or furr of those Northern white Bears that inhabite the colder Regions, is exceeding thick and warm: the like have I observ’d of the hair of a Greenland Deer, which being brought alive to London, I had the opportunity of viewing; its hair was so exceeding thick, long and soft, that I could hardly with my hand, grasp or take hold of his skin, and it seem’d so exceeding warm, as I had never met with any before. And as for the ornamentative use of them, it is most evident in a multitude of creatures, not onely for colour, as the Leopards, Cats, Rhein Deer, &c. but for the shape, as in Horses manes, Cats beards, and several other of the greater sort of terrestrial Animals, but is much more conspicuous, in the Vestments of Fishes, Birds, Insects, of which I shall by and by give some Instances.
As for the skin, the Microscope discovers as great a difference between the texture of those several kinds of Animals, as it does between their hairs; but all that I have yet taken notice of, when tann’d or dress’d, are of a Spongie nature, and seem to be constituted of an infinite company of small long fibres or hairs, which look not unlike a heap of Tow or Okum; every of which fibres seem to have been some part of a Muscle, and probably, whil’st the Animal was alive, might have its distinct function, and serve for the contraction and relaxation of the skin, and for the stretching and shrinking of it this or that way.
And indeed, without such a kind of texture as this, which is very like that of Spunk it would seem very strange, how any body so strong as the skin of an Animal usually is, and so close as it seems, whil’st the Animal is living, should be able to suffer so great an extension any ways, without at all hurting or dilacerating any part of it. But, since we are inform’d by the Microscope, that it consists of a great many small filaments, which are implicated, or intangled one within another, almost no otherwise then the hairs in a lock of Wool, or the flakes in a heap of Tow, though not altogether so loose, but the filaments are here and there twisted, as ’twere, or interwoven, and here and there they join and unite with one another, so as indeed the whole skin seems to be but one piece, we need not much wonder: And though these fibres appear not through a Microscope exactly jointed and contex’d, as in Sponge; yet, as I formerly hinted, I am apt to think, that could we find some way of discovering the texture of it, whil’st it invests the living Animal, or had some very easie way of separating the pulp or intercurrent juices, such as in all probability fill those Interstitia, without dilacerating, brusing, or otherwise spoiling the texture of it (as it seems to be very much by the ways of tanning and dressing now us’d) we might discover a much more curious texture then I have hitherto been able to find; perhaps somewhat like that of Sponges.
That of Chamoise Leather is indeed very much like that of Spunk, save onely that the filaments seem nothing neer so even and round, nor altogether so small, nor has it so curious joints as Spunk has, some of which I have lately discover’d like those of a Sponge, and perhaps all these three bodies may be of the same kind of substance, though two of them indeed are commonly accounted Vegetable (which, whether they be so or no, I shall not now dispute) But this seems common to all three, that they undergo a tanning or dressing, whereby the interspers’d juices are wasted and wash’d away before the texture of them can be discover’d.
What their way is of dressing, or curing Sponges, I confess, I cannot learn; but the way of dressing Spunk, is, by boiling it a good while in a strong Lixivium, and then beating it very well; and the manner of dressing Leather is sufficiently known.
It were indeed extremely desirable, if such a way could be found whereby the Parenchyma or flesh of the Muscles, and several other parts of the body, might be wash’d, or wafted clean away, without vitiating the form of the fibrous parts or vessells of it, for hereby the texture of those parts, by the help of a good Microscope, might be most accurately found.
But to digress no further, we may, from this discovery of the Microscope, plainly enough understand how the skin, though it looks so close as it does, comes to give a passage to so vast a quantity of excrementitious substances, as the diligent Sanctorius has excellently observed it to do, in his medicina statica; for it seems very probable, from the texture after dressing, that there are an infinite of pores that every way pierce it, and that those pores are onely fill’d with some kind of juice, or some very pulpy soft substance, and thereby the steams may almost as easily find a passage through such a fluid vehicle as the vaporous bubbles which are generated at the bottom of a Kettle of hot water do find a passage through that fluid medium into the ambient Air.
Nor is the skin of animals only thus pervious, but even those of vegetables also seem to be the same; for otherwise I cannot conceive why, if two sprigs of Rosemary (for Instance) be taken as exactly alike in all particulars as can be, and the one be set with the bottom in a Glass of water, and the other be set just without the Glass, but in the Air onely, though you stop the lower end of that in the Air very carefully with Wax, yet shall it presently almost wither, whereas the other that seems to have a supply from the subjacent water by its small pipes, or microscopical pores, preserves its greenness for many days, and sometimes weeks.
Now, this to me, seems not likely to proceed from any other cause then the avolation of the juice through the skin; for by the Wax, all those other pores of the stem are very firmly and closely stop’d up. And from the more or less porousness of the skins or rinds of Vegetables may, perhaps, be somewhat of the reason given, why they keep longer green, or sooner wither; for we may observe by the bladdering and craking of the leaves of Bays, Holly, Laurel, &c. that their skins are very close, and do not suffer so free a passage through them of the included juices.
But of this, and of the Experiment of the Rosemary, I shall elsewhere more fully consider, seeming to me an extreme luciferous Experiment, such as seems indeed very plainly to prove the Schematism or structure of Vegetables altogether mechanical, and as necessary, that (water and warmth being apply’d to the bottom of the sprig of a Plant) some of it should be carried upwards into the stem, and thence distributed into the leaves, as that the water of the Thames covering the bottom of the Mills at the Bridge foot of London, and by the ebbing and flowing of it, passing strongly by them, should have some part of it convey’d to the Cesterns above, and thence into several houses and Cesterns up and down the City.
Observ. XXXIII. Of the Scales_ of a Soal, and other Fishes._
Having hinted somewhat of the skin and covering of terrestrial Animals, I shall next add an Observation I made on the skin and Scales of a Soal, a small Fish, commonly enough known; and here in Fishes, as well as other Animals, Nature follows its usual method, framing all parts so, as that they are both usefull and ornamental in all its composures, mingling utile and dulce together; and both these designs it seems to follow, though our unassisted senses are not able to perceive them: This is not onely manifest in the covering of this Fish, but in multitudes of others, which it would be too long to enumerate, witness particularly that small Sand Shell, which I mention’d in the XI. Observation, and infinite other small Shells and Scales, divers of which I have view’d. This skin I view’d, was flead from a pretty large Soal, and then expanded and dry’d, the inside of it, when dry, to the naked eye, look’d very like a piece of Canvass, but the Microscope discover’d that texture to be nothing else, but the inner ends of those curious Scolop’d Scales I, I, I, in the second Figure of the XXI. Scheme, namely, the part of GGGG (of the larger representation of a single Scale, in the first Figure of the same Scheme) which on the back side, through an ordinary single Magnifying Glass, look’d not unlike the Tyles on an house.
The outside of it, to the naked eye, exhibited nothing more of ornament, save the usual order of ranging the Scales into a triagonal form, onely the edges seem’d a little to shine, the finger being rubb’d from the tail-wards towards the head, the Scales seem’d to stay and raze it; But through an ordinary Magnifying glass, it exhibited a most curiously carved and adorned surface, such as is visible in the second Figure, each of those (formerly almost imperceptible) Scales appearing much of the shape I, I, I, that is, they were round, and protuberant, and somewhat shap’d like a Scolop, the whole Scale being creas’d with curiously wav’d and indented ridges, with proportionable furrows between; each of which was terminated with a very sharp transparent bony substance, which, like so many small Turnpikes, seem’d to arm the edges.
The back part KKK was the skin into which each of these Scales were very deeply fix’d, in the curious regular order, visible in the second Figure. The length and shape of the part of the Scale which was buried by the skin, is evidenced by the first Figure; which is the representation of one of them pluck’d out and view’d through a good Microscope, namely, the part LFGGFL, wherein is also more plainly to be seen, the manner of carving of the scolopt part of every particular Scale, how each ridge or barr EEE is alternately hollowed or engraven, and how every gutter between them is terminated with very transparent and hard pointed spikes, and how every other of these, as AAAA, are much longer then the interjacent ones, DDD.
The texture or form also of the hidden part appears, namely, the middle part, GGG, seems to consist of a great number of small quills or pipes, by which, perhaps, the whole may be nourished; and the side parts FF consist of a more fibrous texture, though indeed the whole Scale seem’d to be of a very tough gristly substance like the larger Scales of other Fishes.
The Scales of the skin of a Dog-fish (which is us’d by such as work in Wood, for the smoothing of their work, and consists plainly enough to the naked eye, of a great number off small horny points) through the Microscope appear’d each of them curiously ridg’d, and very neatly carved; and indeed, you can hardly look on the scales of any Fish, but you may discover abundance of curiosity and beautifying; and not only in these Fishes, but in the shells and crusts or armour of most sorts of Marine Animals so invested.
Observ. XXXIV. Of the Sting of a Bee.
The Sting of a Bee, delineated in the second Figure of the XVI. Scheme, seems to be a weapon of offence, and is as great an Instance, that Nature did really intend revenge as any, and that first, because there seems to be no other use of it. Secondly, by reason of its admirable shape, seeming to be purposely shap’d for that very end. Thirdly, from the virulency of the liquor it ejects, and the sad effects and symptoms that follow it.
But whatever be the use of it, certain it is, that the structure of it is very admirable; what it appears to the naked eye, I need not describe, the thing being known almost to every one, but it appears through the Microscope, to consist of two parts, the one a sheath, without a chape or top, shap’d almost like the Holster of a Pistol, beginning at d, and ending at b, this sheath I could most plainly perceive to be hollow, and to contain in it, both a Sword or Dart, and the poisonous liquor that causes the pain. The sheath or case seem’d to have several joints or settings together, marked by fghiklmno, it was arm’d moreover neer the top, with several crooks or forks (pqrst) on one side, and (pqrstu) on the other, each of which seem’d like so many Thorns growing on a briar, or rather like so many Cat’s Claws; for the crooks themselves seem’d to be little sharp transparent points or claws, growing out of little protuberancies on the side of the sheath, which, by observing the Figure diligently, is easie enough to be perceiv’d; and from several particulars, I suppose the Animal has a power of displaying them, and shutting them in again as it pleases, as a Cat does its claws, or as an Adder or Viper can its teeth or fangs.
The other part of the Sting was the Sword, as I may so call it, which is sheath’d, as it were, in it, the top of which ab appears quite through at the smaller end, just as if the chape of the sheath of a Sword were lost, and the end of it appear’d beyond the Scabbard; the end of this Dart(a) was very sharp, and it was arm’d likewise with the like Tenter-hooks or claws with those of the sheath, such as (vxy, xyzz) these crooks, I am very apt to think, can be clos’d up also, or laid flat to the sides of the Sword when it is drawn into the Scabbard, as I have several times observ’d it to be, and can be spred again or extended when ever the Animal pleases.
The consideration of which very pretty structure, has hinted to me, that certainly the use of these claws seems to be very considerable, as to the main end of this Instrument, for the drawing in, and holding the sting in the flesh; for the point being very sharp, the top of the Sting or Dagger (ab) is very easily thrust into an Animal’s body, which being once entred, the Bee, by endeavouring to pull it into the sheath, draws (by reason of the crooks (vxy) and (xyzz) which lay hold of the skin on either side) the top of the sheath (tsrv) into the skin after it, and the crooks t, s, and r, v, being entred, when the Bee endeavours to thrust out the top of the sting out of the sheath again, they lay hold of the skin on either side, and do not onely keep the sheath from sliding back, but helps the top inwards, and thus, by an alternate and successive retracting and emitting of the Sting in and out of the sheath, the little enraged creature by degrees makes his revengfull weapon pierce the toughest and thickest Hides of his enemies, in so much that some few of these stout and resolute soldiers with these little engines, do often put to flight a huge masty Bear, one of their deadly enemies, and thereby shew the world how much more considerable in Warr a few skilfull Engineers and resolute soldiers politickly order’d, that know how to manage such engines, are, then a vast unweildy rude force, that confides in, and acts onely by, its strength. But (to proceed) that he thus gets in his Sting into the skin, I conjecture, because, when I have observ’d this creature living, I have found it to move the Sting thus, to and fro, and thereby also, perhaps, does, as ’twere, pump or force out the poisonous liquor, and make it hang at the end of the sheath about b in a drop. The crooks, I suppose also to be the cause why these angry creatures, hastily removing themselves from their revenge, do often leave these weapons behind them, sheath’d, as ’twere, in the flesh, and, by that means, cause the painfull symptoms to be greater, and more lasting, which are very probably caus’d, partly by the piercing and tearing of the skin by the Sting, but chiefly by the corrosive and poisonous liquor that is by this Syringe-pipe convey’d among the sensitive parts thereof and thereby more easily gnaws and corrodes those tender fibres: As I have shewed in the description of a Nettle and of Cowhage.
Observ. XXXV. Of the contexture and shape of the particles of Feathers.
Examining several sorts of Feathers, I took notice of these particulars in all sorts of wing-Feathers, especially in those which serv’d for the beating of the air in the action of flying.
That the outward surface of the Quill and Stem was of a very hard, stiff, and horny substance, which is obvious enough, and that the part above the Quill was fill’d with a very white and light pith, and, with the Microscope, I found this pith to be nothing else, but a kind of natural congeries of small bubbles, the films of which seem to be of the same substance with that of the Quill, that is, of a stiff transparent horny substance.
Which particular seems to me, very worthy a more serious consideration; For here we may observe Nature, as ’twere, put to its shifts, to make a substance, which shall be both light enough, and very stiff and strong, without varying from its own establish’d principles, which we may observe to be such, that very strong bodies are for the most part very heavie also, a strength of the parts usually requiring a density, and a density a gravity; and therefore should Nature have made a body so broad and so strong as a Feather, almost, any other way then what it has taken, the gravity of it must necessarily have many times exceeded this; for this pith seems to be like so many stops or cross pieces in a long optical tube, which do very much contribute to the strength of the whole, the pores of which were such, as that they seem’d not to have any communication with one another, as I have elsewhere hinted.
But the Mechanism of Nature is usually so excellent, that one and the same substance is adapted to serve for many ends. For the chief use of this, indeed, seems to be for the supply of nourishment to the downy or feathery part of the stem; for ’tis obvious enough in all sorts of Feathers, that ’tis plac’d just under the roots of the branches that grow out of either side of the quill or stalk, and is exactly shap’d according to the ranking of those branches, coming no lower into the quill, then just the beginning of the downy branches, and growing onely on the under side of the quill where those branches do so. Now, in a ripe Feather (as one may call it) it seems difficult to conceive how the Succus nutritius should be convey’d to this pith; for it cannot, I think, be well imagin’d to pass through the substance of the quill, since, having examin’d it with the greatest diligence I was able, I could not find the least appearance of pores; but he that shall well examine an unripe or pinn’d Feather, will plainly enough perceive the Vessel for the conveyance of it to be the thin filmy pith (as ’tis call’d) which passes through the middle of the quill.
As for the make and contexture of the Down it self, it is indeed very rare and admirable, and such as I can hardly believe, that the like is to be discover’d in any other body in the world; for there is hardly a large Feather in the wing of a Bird, but contains neer a million of distinct parts, and every one of them shap’d in a most regular & admirable form, adapted to a particular Design: For examining a middle ciz’d Goose-quill, I easily enough found with my naked eye, that the main stem of it contain’d about 300. longer and more Downy branchings upon one side, and as many on the other of more stiff but somewhat shorter branchings. Many of these long and downy branchings, examining with an ordinary Microscope, I found divers of them to contain neer 1200. small leaves (as I may call them, such as EF of the first Figure of the 22. Scheme) and as many stalks on the other side, such as IK of the same Figure, each of the leaves or branchings, EF, seem’d to be divided into about sixteen or eighteen small joints, as may be seen plainly enough in the Figure, out of most of which there seem to grow small long fibres, such as are express’d in the Figure, each of them very proportionably shap’d according to its position, or place on the stalk EF; those on the under side of it, namely, 1, 2, 3, 4, 5, 6, 7, 8, 9, &c. being much longer then those directly opposite to them on the upper; and divers of them, such as 2, 3, 4, 5, 6, 7, 8, 9, &c. were terminated with small crooks, much resembling those small crooks, which are visible enough to the naked eye, in the seed-buttons of Bur-docks. The stalks likewise, IK on the other side, seem’d divided into neer as many small knotted joints, but without any appearance of strings or crooks, each of them about the middle K, seem’d divided into two parts by a kind of fork, one side of which, namely, KL, was extended neer the length of KI, the other, M, was very short.
The transverse Sections of the stems of these branchings, manifested the shape or figure of it to be much like INOE, which consisted of a horny skin or covering, and a white seemingly frothy pith, much like the make of the main stem of a Feather.
The use of this strange kind of form, is indeed more admirable then all the rest, and such as deserves to be much more seriously examin’d and consider’d, then I have hitherto found time or ability to do; for certainly, it may very much instruct us in the nature of the Air, especially as to some properties of it.
The stems of the Downy branches INOE, being rang’d in the order visible enough to the naked eye, at the distance of IF, or somewhat more, the collateral stalks and leaves (if I may so call those bodies I newly described) are so rang’d, that the leaves or hairy stalks of the one side lie at top, or are incumbent on the stalks of the other, and cross each other, much after the manner express’d in the second Figure of the 22. Scheme, by which means every of those little hooked fibres of the leaved stalk get between the naked stalks, and the stalks being full of knots, and a prety way dis-join’d, so as that the fibres can easily get between them, the two parts are so closely and admirably woven together, that it is able to impede, for the greatest part, the transcursion of the Air; and though they are so exceeding small, as that the thickness of one of these stalks amounts not to a 500. part of an Inch, yet do they compose so strong a texture, as, notwithstanding the exceeding quick and violent beating of them against the Air, by the strength of the Birds wing, they firmly hold together. And it argues an admirable providence of Nature in the contrivance and fabrick of them; for their texture is such, that though by any external injury the parts of them are violently disjoyn’d, so as that the leaves and stalks touch not one another, and consequently several of these rents would impede the Bird’s flying; yet, for the most part, of themselves they readily re-join and re-contex themselves, and are easily by the Birds stroking the Feather, or drawing it through its Bill, all of them settled and woven into their former and natural posture; for there are such an infinite company of those small fibres in the under side of the leaves, and most of them have such little crooks at their ends, that they readily catch and hold the stalks they touch.
From which strange contexture, it seems rational to suppose that there is a certain kind of mesh or hole so small, that the Air will not very easily pass through it, as I hinted also in the sixth Observation about small Glass Canes, for otherwise it seems probable, that Nature would have drawn over some kind of thin film which should have covered all those almost square meshes or holes, there seeming through the Microscope to be more then half of the surface of the Feather which is open and visibly pervious; which conjecture will yet seem more probable from the texture of the brushie wings of the Tinea argentea, or white Feather wing’d moth, which I shall anone describe. But Nature, that knows best its own laws, and the several properties of bodies, knows also best how to adapt and fit them to her designed ends, and whoso would know those properties, must endeavour to trace Nature in its working, and to see what course she observes. And this I suppose will be no inconsiderable advantage which the Schematisms and Structures of Animate bodies will afford the diligent enquirer, namely, most sure and excellent instructions, both as to the practical part of Mechanicks and to the Theory and knowledge of the nature of the bodies and motions.
Observ. XXXVI. Of Peacocks, Ducks, and other Feathers_ of changeable colours._
The parts of the Feathers of this glorious Bird appear, through the Microscope, no less gaudy then do the whole Feathers; for, as to the naked eye ’tis evident that the stem or quill of each Feather in the tail sends out multitudes of Lateral branches, such as AB in the third Figure of the 22. Scheme represents a small part of about ¹⁄₃₂ part of an Inch long, and each of the lateral branches emit multitudes of little sprigs, threads or hairs on either side of them, such as CD, CD, CD, so each of those threads in the Microscope appears a large long body, consisting of a multitude of bright reflecting parts, whose Figure ’tis no easie matter to determine, as he that examines it shall find; for every new position of it to the light makes it perfectly seem of another form and shape, and nothing what it appear’d a little before; nay, it appear’d very differing ofttimes from so seemingly inconsiderable a circumstance, that the interposing of ones hand between the light and it, makes a very great change, and the opening or shutting a Casement and the like, very much diversifies the appearance. And though, by examining the form of it very many ways, which would be tedious here to enumerate, I suppose I have discover’d the true Figure of it, yet oftentimes, upon looking on it in another posture, I have almost thought my former observations deficient, though indeed, upon further examination, I have found even those also to confirm them.
These threads therefore I find to be a congeries of small Laminæ or plates, as eeeee, &c. each of them shap’d much like this of abcd, in the fourth Figure, the part ac being a ridge, prominency, or stem, and b and d the corners of two small thin Plates that grow unto the small stalk in the middle, so that they make a kind of little feather; each of these Plates lie one close to another, almost like a company of sloping ridge or gutter Tyles; they grow on each side of the stalk opposite to one another, by two and two, from top to bottom, in the manner express’d in the fifth Figure, the tops of the lower covering the roots of the next above them; the under side of each of these laminated bodies, is of a very dark and opacous substance, and suffers very few Rays to be trajected, but reflects them all toward that side from whence they come, much like the foil of a Looking-glass; but their upper sides seem to me to consist of a multitude of thin plated bodies, which are exceeding thin, and lie very close together, and thereby, like mother of Pearl shells, do not onely reflect a very brisk light, but tinge that light in a most curious manner; and by means of various positions, in respect of the light, they reflect back now one colour, and then another, and those most vividly.
Now, that these colours are onely fantastical ones, that is, such as arise immediately from the refractions of the light, I found by this, that water wetting these colour’d parts, destroy’d their colours, which seem’d to proceed from the alteration of the reflection and refraction. Now, though I was not able to see those hairs at all transparent by a common light, yet by looking on them against the Sun, I found them to be ting’d with a darkish red colour, nothing a-kin to the curious and lovely greens and blues they exhibited.
What the reason of colour seems to be in such thin plated bodies, I have elsewhere shewn. But how water cast upon those threads destroys their colours, I suppose to be perform’d thus; The water falling upon these plated bodies from its having a greater congruity to Feathers then the Air, insinuates it self between those Plates, and so extrudes the strong reflecting Air, whence both these parts grow more transparent, as the Microscope informs, and colourless also, at best retaining a very faint and dull colour. But this wet being wasted away by the continual evaporations and steams that pass through them from the Peacock, whil’st that Bird is yet alive, the colours again appear in their former luster, the interstitia of these Plates being fill’d with the strongly reflecting Air.
The beauteous and vivid colours of the Feathers of this Bird, being found to proceed from the curious and exceeding smalness and fineness of the reflecting parts, we have here the reason given us of all those gauderies in the apparel of other Birds also, and how they come to exceed the colours of all other kinds of Animals, besides Insects; for since (as we here, and elsewhere also shew) the vividness of a colour, depends upon the fineness and transparency of the reflecting and refracting parts; and since our Microscope discovers to us, that the component parts of feathers are such, and that the hairs of Animals are otherwise; and since we find also by the Experiment of that Noble and most Excellent Person I formerly named; that the difference between Silk and Flax, as to its colour, is nothing else (for Flax reduc’d to a very great fineness of parts, both white and colour’d, appears as white and as vivid as any Silk, but loses that brightness and its Silken aspect as soon as it is twisted into thread, by reason that the component parts, though very small and fine, are yet pliable flakes, and not cylinders, and thence, by twisting, become united into one opacous body, whereas the threads of Silk and Feathers retain their lustre, by preserving their cylindrical form intire without mixing; so that each reflected and refracted beam that composes the gloss of Silk, preserves its own property of modulating the light intire); And since we find the same confirm’d by many other Experiments elsewhere mentioned, I think we may safely conclude this for an Axiome, that wheresoever we meet with transparent bodies, spun out into very fine parts, either cleer, or any ways ting’d, the colours resulting from such a composition must necessarily be very glorious, vivid, and cleer, like those of Silk and Feathers. This may perhaps hint some usefull way of making other bodies, besides Silk, be susceptible of bright tinctures, but of this onely by the by.
The changeable colour’d Feathers also of Ducks, and several other Birds, I have found by examination with my Microscope, to proceed from much the same causes and textures.
Observ. XXXVII. Of the Feet of Flies, and several other Insects.
The foot of a Fly (delineated in the first Figure of the 23. Scheme, which represents three joints, the two Tallons, and the two Pattens in a flat posture; and in the second Figure of the same Scheme, which represents onely one joint, the Tallons and Pattens in another posture) is of a most admirable and curious contrivance, for by this the Flies are inabled to walk against the sides of Glass, perpendicularly upwards, and to contain themselves in that posture as long as they please; nay, to walk and suspend themselves against the under surface of many bodies, as the ceiling of a room, or the like, and this with as great a seeming facility and firmness, as if they were a kind of Antipodes, and had a tendency upwards, as we are sure they have the contrary, which they also evidently discover, in that they cannot make themselves so light, as to stick or suspend themselves on the under surface of a Glass well polish’d and cleans’d; their suspension therefore is wholly to be ascrib’d to some Mechanical contrivance in their feet; which, what it is, we shall in brief explain, by shewing, that its Mechanism consists principally in two parts, that is, first its two Claws, or Tallons, and secondly, two Palms, Pattens, or Soles.
The two Tallons are very large, in proportion to the foot, and handsomely shap’d in the manner describ’d in the Figures, by AB, and AC, the bigger part of them from A to dd, is all hairy, or brisled, but toward the top, at C and B smooth, the tops or points, which seem very sharp turning downwards and inwards, are each of them mov’d on a joint at A, by which the Fly is able to open or shut them at pleasure, so that the points B and C being entered in any pores, and the Fly endeavouring to shut them, the Claws not onely draw one against another, and so fasten each other, but they draw the whole foot, GGADD forward, so that on a soft footing, the tenters or points GGGG, (whereof a Fly has about ten in each foot, to wit, two in every joint) run into the pores, if they find any, or at least make their way; and this is sensible to the naked eye, in the feet of a Chafer, which, if he be suffer’d to creep over the hand, or any other part of the skin of ones body, does make his steps as sensible to the touch as the sight.
But this contrivance, as it often fails the Chafer, when he walks on hard and close bodies, so would it also our Fly, though he be a much lesser, and nimbler creature, and therefore Nature has furnish’d his foot with another additament much more curious and admirable, and that is, with a couple of Palms, Pattens or Soles DD, the structure of which is this:
From the bottom or under part of the last joint of his foot, K, arise two small thin plated horny substances, each consisting of two flat pieces, DD, which seem to be flexible, like the covers of a Book, about FF, by which means, the plains of the two sides EE, do not always lie in the same plain, but may be sometimes shut closer, and so each of them may take a little hold themselves on a body; but that is not all, for the under sides of these Soles are all beset with small brisles, or tenters, like the Wire teeth of a Card used for working Wool, the points of all which tend forwards, hence the two Tallons drawing the feet forwards, as I before hinted, and these being applied to the surface of the body with all the points looking the contrary way, that is, forwards and outwards, if there be any irregularity or yielding in the surface of the body, the Fly suspends it self very firmly and easily, without the access or need of any such Sponges fill’d with an imaginary gluten, as many have, for want of good Glasses, perhaps, or a troublesome and diligent examination, suppos’d.
Now, that the Fly is able to walk on Glass, proceeds partly from some ruggedness of the surface: and chiefly from a kind of tarnish, or dirty smoaky substance, which adheres to the surface of that very hard body; and though the pointed parts cannot penetrate the substance of Glass, yet may they find pores enough in the tarnish, or at least make them.
This Structure I somewhat the more diligently survey’d, because I could not well comprehend, how, if there were such a glutinous matter in those supposed Sponges, as most (that have observ’d that Object in a Microscope) have hitherto believ’d, how, I say, the Fly could so readily unglew and loosen its feet: and, because I have not found any other creature to have a contrivance any ways like it, and chiefly, that we might not be cast upon unintelligible explications of the Phænomena of Nature, at least others then the true ones, where our senses were able to furnish us with an intelligible, rationall and true one.
Somewhat a like contrivance to this of Flies shall we find in most other Animals, such as all kinds of Flies and case-wing’d creatures; nay, in a Flea, an Animal abundantly smaller then this Fly. Other creatures, as Mites, the Land-Crab, &c. have onely one small very sharp Tallon at the end of each of their legs, which all drawing towards the center or middle of their body, inable these exceeding light bodies to suspend and fasten themselves to almost any surface.
Which how they are able to do, will not seem strange, if we consider, first, how little body there is in one of these creatures compar’d to their superficies, or outside, their thickness, perhaps, oftentimes, not amounting to the hundredth part of an Inch: Next, the strength and agility of these creatures compar’d to their bulk, being, proportionable to their bulk, perhaps, an hundred times stronger then an Horse or Man. And thirdly, if we consider that Nature does always appropriate the instruments, so as they are the most fit and convenient to perform their offices, and the most simple and plain that possibly can be; this we may see further verify’d also in the foot of a Louse which is very much differing from those I have been describing, but more convenient and necessary for the place of its habitation, each of his leggs being footed with a couple of small claws which he can open or shut at pleasure, shap’d almost like the claws of a Lobster or Crab, but with appropriated contrivances for his peculiar use, which being to move its body to and fro upon the hairs of the creature it inhabits, Nature has furnish’d one of its claws with joints, almost like the joints of a man’s fingers, so as thereby it is able to encompass or grasp a hair as firmly as a man can a stick or rope.
Nor, is there a less admirable and wonderfull Mechanism in the foot of a Spider, whereby he is able to spin, weave, and climb, or run on his curious transparent clew, of which I shall say more in the description of that Animal.
And to conclude, we shall in all things find, that Nature does not onely work Mechanically, but by such excellent and most compendious, as well as stupendious contrivances, that it were impossible for all the reason in the world to find out any contrivance to do the same thing that should have more convenient properties. And can any be so sottish, as to think all those things the productions of chance? Certainly, either their Ratiocination must be extremely depraved, or they did never attentively consider and contemplate the Works of the Al-mighty.
Observ. XXXVIII. Of the Structure and motion of the Wings of Flies.
The Wings of all kinds of Insects, are, for the most part, very beautifull Objects, and afford no less pleasing an Object to the mind to speculate upon, then to the eye to behold. This of the blue Fly, among the rest, wants not its peculiar ornaments and contrivances; it grows out of the Thorax, or middle part of the body of a Fly, and is seated a little beyond the center of gravity in the body towards the head, but that Excentricly is curiously balanc’d; first, by the expanded Area of the wings which lies all more backwards then the root, by the motion of them, whereby the center of their vibration is much more backwards towards the tail of the Fly then the root of the wing is. What the vibrative motion of the wings is, and after what manner they are moved, I have endeavoured by many trials to find out: And first for the manner of their motion, I endeavoured to observe several of those kind of small spinning Flies, which will naturally suspend themselves, as it were, pois’d and steady in one place of the air, without rising or falling, or moving forwards or backwards; for by looking down on those, I could by a kind of faint shadow, perceive the utmost extremes of the vibrative motion of their wings, which shadow, whil’st they so endeavoured to suspend themselves, was not very long, but when they endeavour’d to flie forwards, it was somewhat longer; next, I tried it, by fixing the leggs of a Fly upon the top of the stalk of a feather, with Glew, Wax, &c. and then making it endeavour to flie away; for being thereby able to view it in any posture, I collected that the motion of the wing was after this manner.
The extreme limits of the vibrations were usually somewhat about the length of the body distant from one another, oftentimes shorter, and sometimes also longer; that the formost limit was usually a little above the back, and the hinder somwhat beneath the belly; between which two limits, if one may ghess by the sound, the wing seem’d to be mov’d forwards and backwards with an equal velocity: And if one may (from the shadow or faint representation the wings afforded, and from the consideration of the nature of the thing) ghess at the posture or manner of the wings moving between them, it seem’d to be this: The wing being suppos’d placed in the upmost limit, seems to be put so that the plain of it lies almost horizontal, but onely the forepart does dip a little, or is somewhat more deprest; in this position is the wing vibrated or mov’d to the lower limit, being almost arrived at the lower limit, the hinder part of the wing moving somewhat faster then the former, the Area of the wing begins to dip behind, and in that posture seems it to be mov’d to the upper limit back again, and thence back again in the first posture, the former part of the Area dipping again, as it is moved downwards by means of the quicker motion of the main stem which terminates or edges the forepart of the wing. And these vibrations or motions to and fro between the two limits seem so swift, that ’tis very probable (from the sound it affords, if it be compar’d with the vibration of a musical string, tun’d unison to it) it makes many hundreds, if not some thousands of vibrations in a second minute of time. And, if we may be allow’d to ghess by the sound, the wing of a Bee is yet more swift, for the tone is much more acute, and that, in all likelihood, proceeds from the exceeding swift beating of the air by the small wing.
And it seems the more likely too, because the wing of a Bee is less in proportion to its body, then the other wing to the body of a Fly; so that for ought I know, it may be one of the quickest vibrating spontaneous motions of any in the world; and though perhaps there may be many Flies in other places that afford a yet more shrill note with their wings, yet ’tis most probable that the quickest vibrating spontaneous motion is to be found in the wing of some creature. Now, if we consider the exceeding quickness of these Animal spirits that must cause these motions, we cannot chuse but admire the exceeding vividness of the governing faculty or Anima of the Insect, which is able to dispose and regulate so the motive faculties, as to cause every peculiar organ, not onely to move or act so quick, but to do it also so regularly.
Whil’st I was examining and considering the curious Mechanism of the wings, I observ’d that under the wings of most kind of Flies, Bees, &c. there were plac’d certain pendulums or extended drops (as I may so call them from their resembling motion and figure) for they much resembled a long hanging drop of some transparent viscous liquor; and I observed them constantly to move just before the wings of the Fly began to move, so that at the first sight I could not but ghess, that there was some excellent use, as to the regulation of the motion of the wing, and did phancy, that it might be something like the handle of a Cock, which by vibrating to and fro, might, as ’twere, open and shut the Cock, and thereby give a passage to the determinate influences into the Muscles; afterwards, upon some other trials, I suppos’d that they might be for some use in respiration, which for many reasons I suppose those Animals to use, and, me thought, it was not very improbable, but that they might have convenient passages under the wings for the emitting, at least, of the air, if not admitting, as in the gills of Fishes is most evident; or, perhaps, this Pendulum might be somewhat like the staff to a Pump, whereby these creatures might exercise their Analogous lungs, and not only draw in, but force out, the air they live by: but these were but conjectures, and upon further examination seem’d less probable.
The fabrick of the wing, as it appears through a moderately magnifying Microscope, seems to be a body consisting of two parts, as is visible in the 4. Figure of the 23. Scheme; and by the 2. Figure of the 26. Scheme; the one is a quilly or finny substance, consisting of several long, slender and variously bended quills or wires, something resembling the veins of leaves; these are, as ’twere, the finns or quills which stiffen the whole Area, and keep the other part distended, which is a very thin transparent skin or membrane variously folded, and platted, but not very regularly, and is besides exceeding thickly bestuck with innumerable small bristles, which are onely perceptible by the bigger magnifying Microscope, and not with that neither, but with a very convenient augmentation of sky-light projected on the Object with a burning Glass, as I have elsewhere shew’d, or by looking through it against the light.
In steed of these small hairs, in several other Flies, there are infinite of small Feathers, which cover both the under and upper sides of this thin film as in almost all the sorts of Butterflies and Moths: and those small parts are not onely shap’d very much like the feathers of Birds, but like those variegated with all the variety of curious bright and vivid colours imaginable; and those feathers are likewise so admirably and delicately rang’d, as to compose very fine flourishings and ornamental paintings, like Turkie and Persian Carpets, but of far more surpassing beauty, as is evident enough to the naked eye, in the painted wings of Butterflies, but much more through an ordinary Microscope.
Intermingled likewise with these hairs, may be perceived multitudes of little pits, or black spots, in the extended membrane, which seem to be the root of the hairs that grow on the other side; these two bodies seem dispers’d over the whole surface of the wing.
The hairs are best perceiv’d, by looking through it against the light, or, by laying the wing upon a very white piece of Paper, in a convenient light, for thereby every little hair most manifestly appears; a Specimen of which you may observe drawn in the fourth Figure of the 23. Scheme, AB, CD, EF whereof represent some parts of the bones or quills of the wing, each of which you may perceive to be cover’d over with a multitude of scales, or bristles, the former AB, is the biggest stem of all the wing, and may be properly enough call’d the cut-air, it being that which terminates and stiffens the formost edge of the wing; the fore-edge of this is arm’d with a multitude of little brisles, or Tenter-hooks, in some standing regular and in order, in others not; all the points of which are directed from the body towards the tip of the wing, nor is this edge onely thus fring’d, but even all the whole edge of the wing is covered with a small fringe, consisting of short and more slender brisles.
This Subject, had I time, would afford excellent matter for the contemplation of the nature of wings and of flying, but, because I may, perhaps, get a more convenient time to prosecute that speculation, and recollect several Observations that I have made of that particular. I shall at present proceed to
Observ. XXXIX. Of the Eyes and Head of a Grey drone-Fly_, and of several other creatures._
I took a large grey Drone-Fly, that had a large head, but a small and slender body in proportion to it, and cutting off its head, I fix’d it with the forepart or face upwards upon my Object Plate (this I made choice of rather then the head of a great blue Fly, because my enquiry being now about the eyes, I found this Fly to have, first the biggest clusters of eyes in proportion to his head, of any small kind of Fly that I have yet seen, it being somewhat inclining towards the make of the large Dragon-Flies. Next, because there is a greater variety in the knobs or balls of each cluster, then is of any small Fly.) Then examining it according to my usual manner, by varying the degrees of light, and altering its position to each kinde of light, I drew that representation of it which is delineated in the 24. Scheme, and found these things to be as plain and evident, as notable and pleasant.
First, that the greatest part of the face, nay, of the head, was nothing else but two large and protuberant bunches, or prominent parts, ABCDEA, the surface of each of which was all cover’d over, or shap’d into a multitude of small Hemispheres, plac’d in a triagonal order, that being the closest and most compacted, and in that order, rang’d over the whole surface of the eye in very lovely rows, between each of which, as is necessary, were left long and regular trenches, the bottoms of every of which, were perfectly intire and not at all perforated or drill’d through, which I most certainly was assured of, by the regularly reflected Image of certain Objects which I mov’d to and fro between the head and the light. And by examining the Cornea or outward skin, after I had stript it off from the several substances that lay within it, and by looking both upon the inside and against the light.
Next, that of those multitudes of Hemispheres, there were observable two degrees of bigness, the half of them that were lowermost, and look’d toward the ground or their own leggs, namely, CDE, CDE being a pretty deal smaller then the other, namely, ABCE, ABCE, that look’d upward, and side-ways, or foreright, and backward, which variety I have not found in any other small Fly.
Thirdly, that every one of these Hemispheres, as they seem’d to be pretty neer the true shape of a Hemisphere, so was the surface exceeding smooth and regular, reflecting as exact, regular, and perfect an Image of any Object from the surface of them, as a small Ball of Quick-silver of that bigness would do, but nothing neer so vivid, the reflection from these being very languid, much like the reflection from the outside of Water, Glass, Crystal, &c. In so much that in each of these Hemispheres, I have been able to discover a Land-scape of those things which lay before my window, one thing of which was a large Tree, whose trunk and top I could plainly discover, as I could also the parts of my window, and my hand and fingers, if I held it between the Window and the Object; a small draught of nineteen of which, as they appear’d in the bigger Magnifying-glass to reflect the Image of the two windows of my Chamber, are delineated in the third Figure of the 23. Scheme.
Fourthly, that these rows were so dispos’d, that there was no quarter visible from his head that there was not some of these Hemispheres directed against, so that a Fly may be truly said to have an eye every way, and to be really circumspect. And it was further observable, that that way where the trunk of his body did hinder his prospect backward, these protuberances were elevated, as it were, above the plain of his shoulders and back, so that he was able to see backwards also over his back.
