Chapter III: Several kinds of Figures in Water frozen (6)

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

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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.

_Fifthly_, in living Flies, I have observ’d, that when any small mote or dust, which flies up and down the air, chances to light upon any part of these knobs, as it is sure to stick firmly to it and not fall, though through the _Microscope_ it appears like a large stone or stick (which one would admire, especially since it is no ways probable that there is any wet or glutinous matter upon these _Hemispheres_, but I hope I shall render the reason in another place) so the Fly presently makes use of his two fore-feet in stead of eye-lids, with which, as with two Brooms or Brushes, they being all bestuck with Brisles, he often sweeps or brushes off what ever hinders the prospect of any of his _Hemispheres_, and then, to free his leggs from that dirt, he rubs them one against another, the pointed Brisles or Tenters of which looking both one way, the rubbing of them to and fro one against another, does cleanse them in the same manner as I have observ’d those that Card Wool, to cleanse their Cards, by placing their Cards, so as the teeth of both look the same way, and then rubbing them one against another. In the very same manner do they brush and cleanse their bodies and wings, as I shall by and by shew; other creatures have other contrivances for the cleansing and cleering their eyes.

_Sixthly_ that the number of the _Pearls_ or _Hemispheres_ in the clusters of this Fly, was neer 14000. which I judged by numbering certain rows of them several ways, and casting up the whole content, accounting each cluster to contain about seven thousand Pearls, three thousand of which were of a size, and consequently the rows not so thick, and the foure thousand I accounted to be the number of the smaller Pearls next the feet and _proboscis_. Other Animals I observ’d to have yet a greater number, as the _Dragon-Fly_ or _Adderbolt_: And others to have a much less company, as an _Ant_, &c. and several other small Flies and Insects.

_Seventhly_, that the order of these eies or _Hemispheres_ was altogether curious and admirable, they being plac’d in all kind of Flies, and _aerial_ animals, in a most curious and regular ordination of triangular rows, in which order they are rang’d the neerest together that possibly they can, and consequently leave the least pits or trenches between them. But in _Shrimps_, _Crawfishes_, _Lobsters_, and such kinds of _Crustaceous_ water Animals, I have yet observ’d them rang’d in a quadrangular order, the rows cutting each other at right angles, which as it admits of a less number of Pearls in equal surfaces; so have those creatures a recompence made them, by having their eyes a little movable in their heads, which the other altogether want. So infinitely wise and provident do we find all the Dispensations in Nature, that certainly _Epicurus_, and his followers, must very little have consider’d them, who ascrib’d those things to the production of chance, that wil, to a more attentive considerer, appear the products of the highest Wisdom and Providence.

Upon the Anatomy or Dissection of the Head, I observ’d these particulars:

First, that this outward skin, like the _Cornea_ of the eyes of the greater Animals, was both flexible and transparent, and seem’d, through the _Microscope_ perfectly to resemble the very substance of the _Cornea_ of a man’s eye; for having cut out the cluster, and remov’d the dark and _mucous_ stuff that is subjacent to it, I could see it transparent like a thin piece of skin, having as many cavities in the inside of it, and rang’d in the same order as it had _protuberances_ on the outside, and this propriety, I found the same in all the Animals that had it, whether Flies or Shell-Fish.

Secondly, I found that all Animals that I have observ’d with those kind of eyes; have within this _Cornea_, a certain cleer liquor or juice, though in a very little quantity, and,

I observ’d thirdly, that within that cleer liquor, they had a kind of dark _mucous_ lining, which was all spread round within the cavity of the clutter, and seem’d very neer adjoining to it, the colour of which, in some Flies, was grey; in others, black, in others red; in others, of a mix’d colour; in others, spotted; and that the whole clusters, when look’d on whilst the Animal was living, or but newly kill’d, appear’d of the same colour that this coat (as I may so call it) appear’d of, when that outward skin, or _Cornea_, was remov’d.

Fourthly, that the rest of the capacity of the clusters was in some, as in Dragon Flies, &c. hollow, or empty; in others fill’d with some kind of substance; in blue Flies, with a reddish musculous substance, with _fibres_ tending from the center or bottom outwards; and divers other, with various and differing kinds of substances.

That this curious contrivance is the organ of sight to all those various _Crustaceous_ Animals, which are furnish’d with it, I think we need not doubt, if we consider but the several congruities it has with the eyes of greater creatures.

As first, that it is furnish’d with a _Cornea_, with a _transparent humour_, and with a _uvea_ or _retina_, that the Figure of each of the small _Hemispheres_ are very _Spherical_, exactly polish’d, and most vivid, lively and plump, when the Animal is living, as in greater Animals, and in like manner dull, flaccid, and irregular, or shrunk, when the Animal is dead.

Next, that those creatures that are furnish’d with it, have no other organs that have any resemblance to the known eyes of other creatures.

Thirdly, that those which they call the eyes of Crabs, Lobsters, Shrimps, and the like, and are really so, are _Hemispher’d_, almost in the same manner as these of Flies are. And that they really are so, I have very often try’d, by cutting off these little movable knobs, and putting the creature again into the water, that it would swim to and fro, and move up and down as well as before, but would often hit it self against the rocks or stones; and though I put my hand just before its head, it would not at all start or fly back till I touch’d it, whereas whil’st those were remaining, it would start back, and avoid my hand or a stick at a good distance before it touch’d it. And if in _crustaceous_ Sea-animals, then it seems very probable also, that these knobs are the eyes in _crustaceous_ Insects, which are also of the same kind, onely in a higher and more active Element; this the conformity or congruity of many other parts common to either of them, will strongly argue, their _crustaceous_ armour, their number of leggs, which are six, beside the two great claws, which answer to the wings in Insects; and in all kind of Spiders, as also in many other Insects that want wings, we shall find the compleat number of them, and not onely the number, but the very shape, figure, joints, and claws of Lobsters and Crabs, as is evident in Scorpions and Spiders, as is visible in the second _Figure_ of the 31. _Scheme_, and in the little Mite-worm, which I call a Land-crab, describ’d in the second Figure of the 33. _Scheme_, but in their manner of generation being oviparous, &c. And it were very worthy observation, whether there be not some kinds of transformation and metamorphosis in the several states of _crustaceous_ water-animals, as there is in several sorts of Insects; for if such could be met with, the progress of the variations would be much more conspicuous in those larger Animals, then they can be in any kind of Insects our colder Climate affords.

These being their eyes, it affords us a very pretty Speculation to contemplate their manner of vision, which, as it is very differing from that of _biocular_ Animals, so is it not less admirable.

That each of these Pearls or _Hemispheres_ is a perfect eye, I think we need not doubt, if we consider onely the outside or figure of any one of them, for they being each of them cover’d with a transparent protuberant _Cornea_, and containing a liquor within them, resembling the watry or glassie humours of the eye, must necessarily refract all the parallel Rays that fall on them out of the air, into a point not farr distant within them, where (in all probability) the _Retina_ of the eye is placed, and that opacous, dark, and mucous inward coat that (I formerly shew’d) I found to subtend the concave part of the cluster is very likely to be that _tunicle_ or coat, it appearing through the _Microscope_ to be plac’d a little more than a Diameter of those Pearls below or within the _tunica cornea_. And if so, then is there in all probability, a little Picture or Image of the objects without, painted or made at the bottom of the _Retina_ against every one of those Pearls, so that there are as many impressions on the _Retina_ or opacous skin, as there are Pearls or _Hemispheres_ on the cluster. But because it is impossible for any protuberant surface whatsoever, whether _sphærial_ or other, so to refract the Rays that come from farr remote _lateral_ points of any Object as to collect them again, and unite them each in a distinct point, and that onely those Rays which come from some point that lies in the _Axis_ of the Figure produc’d, are so accurately refracted to one and the same point again, and that the _lateral_ Rays, the further they are remov’d, the more imperfect is their refracted confluence; It follows therefore, that onely the Picture of those parts of the external objects that lie in, or neer, the _Axis_ of each _Hemisphere_, are discernably painted or made on the _Retina_ of each _Hemisphere_, and that therefore each of them can distinctly sensate or see onely those parts which are very neer perpendicularly oppos’d to it, or lie in or neer its optick _Axis_. Now, though there may be by each of these eye-pearls, a representation to the Animal of a whole _Hemisphere_ in the same manner as in a man’s eye there is a picture or sensation in the _Retina_ of all the objects lying almost in an _Hemisphere_; yet, as in a man’s eye also, there are but some very few points which liyng in, or neer, the optick _Axis_ are distinctly discern’d: So there may be multitudes of Pictures made of an Object in the several Pearls, and yet but one, or some very few that are distinct; The representation of any object that is made in any other Pearl, but that which is directly, or very neer directly, oppos’d, being altogether confus’d and unable to produce a distinct vision.

So that we see, that though it has pleas’d the All-wise Creator, to indue this creature with such multitudes of eyes, yet has he not indued it with the faculty of seeing more then another creature; for whereas this cannot move his head, at least can move it very little, without moving his whole body, _biocular_ creatures can in an instant (or _the twinkling of an eye_, which, being very quick, is vulgarly used in the same signification) move their eyes so as to direct the optick _Axis_ to any point; nor is it probable, that they are able to see attentively at one time more then one Physical point; for though there be a distinct Image made in every eye, yet ’tis very likely, that the observing faculty is only imploy’d about some one object for which they have most concern.

Now, as we accurately distinguish the site or position of an Object by the motion of the Muscles of the eye requisite to put the optick Line in a direct position, and confusedly by the position of the imperfect Picture of the object at the bottom of the eye; so are these _crustaceous_ creatures able to judge confusedly of the position of objects by the Picture or impression made at the bottom of the opposite Pearl, and distinctly by the removal of the attentive or observing faculty, from one Pearl to another, but what this faculty is, as it requires another place, so a much deeper speculation. Now, because it were impossible, even with this multitude of eye-balls, to see any object distinct (for as I hinted before, onely those parts that lay in, or very neer, the optick Lines could be so) the Infinitely wise Creator has not left the creature without a power of moving the head a little in _Aerial crustaceous_ animals, and the very eyes also in _crustaceous_ Sea-animals; so that by these means they are inabled to direct some optick line or other against any object, and by that means they have the visive faculty as compleat as any Animal that can move its eyes.

Distances of Objects also, ’tis very likely they distinguish, partly by the consonant impressions made in some two convenient Pearls, one in each cluster; for, according as those congruous impressions affect, two Pearls neerer approach’d to each other, the neerer is the Object, and the farther they are distant, the more distant is the Object: partly also by the alteration of each Pearl, requisite to make the Sensation or Picture perfect; for ’tis impossible that the Pictures of two Objects, variously distant, can be perfectly painted, or made on the same _Retina_ or bottom of the eye not altered, as will be very evident to any one that shall attentively consider the nature of refraction. Now, whether this alteration may be in the Figure of the _Cornea_, in the motion of access or recess of the _Retina_ towards the _Cornea_, or in the alteration of a crystalline humour, if such there be, I pretend not to determine; though I think we need not doubt, but that there may be as much curiosity of contrivance and structure in every one of these Pearls, as in the eye of a Whale or Elephant, and the almighty’s _Fiat_ could as easily cause the existence of the one as the other; and as one day and a thousand years are the same with him, so may one eye and ten thousand.

This we may be sure of, that the filaments or sensative parts of the _Retina_ must be most exceedingly curious and minute, since the whole Picture it self is such; what must needs the component parts be of that _Retina_, which distinguishes the part of an object’s Picture that must be many millions of millions less then that in a man’s eye? And how exceeding curious and subtile must the component parts of the _medium_ that conveys light be, when we find the instrument made for its reception or refraction to be so exceedingly small? we may, I think, from this speculation be sufficiently discouraged from hoping to discover by any optick or other instrument the determinate bulk of the parts of the _medium_ that conveys the pulse of light, since we find that there is not less accurateness shewn in the Figure and polish of those exceedingly minute lenticular surfaces, then in those more large and conspicuous surfaces of our own eyes. And yet can I not doubt, but that there is a determinate bulk of those parts, since I find them unable to enter between the parts of Mercury, which being in motion, must necessarily have pores, as I shall elsewhere shew, and here pass by, as being a digression.

As concerning the horns FF, the feelers or smellers, GG, the _Proboscis_ HH, and I, the hairs and brisles, KK, I shall indeavour to describe in the 42. _Observation_.

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Observ. XL. _Of the Teeth of a _Snail_._

I have little more to add of the Teeth of a Snail, besides the Picture of it, which is represented in the first _Figure_ of the 25. _Scheme_, save that his bended body, ABCDEF, which seem’d fashioned very much like a row of small teeth, orderly plac’d in the Gums, and looks as if it were divided into several smaller and greater black teeth, was nothing but one small bended hard bone, which was plac’d in the upper jaw of the mouth of a House-Snail, with which I observ’d this very Snail to feed on the leaves of a Rose-tree, and to bite out pretty large and half round bits, not unlike the Figure of a (C) nor very much differing from it in bigness, the upper part ABCD of this bone, I found to be much whiter, and to grow out of the upper chap of the Snail, GGG, and not to be any thing neer so much creas’d as the lower and blacker part of it HIIHKKH which was exactly shap’d like teeth, the bone growing thinner, or tapering to an edge towards KKK. It seem’d to have nine teeth, or prominent parts IK, IK, IF, &c. which were join’d together by the thinner interpos’d parts of the bone. The Animal to which these teeth belong, is a very _anomalous_ creature, and seems of a kind quite distinct from any other terrestrial Animal or Insect, the Anatomy whereof exceedingly differing from what has been hitherto given of it I should have inserted, but that it will be more proper in another place. I have never met with any kind of Animal whose teeth are all join’d in one, save onely that I lately observ’d, that all the teeth of a Rhinocerot, which grow on either side of its mouth, are join’d into one large bone, the weight of one of which I found to be neer eleven pound _Haverdupois_. So that it seems one of the biggest sort of terrestrial Animals, as well as one of the smallest, has his teeth thus shap’d.

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Observ. XLI. _Of the Eggs of _Silk-worms_, and other Insects._

The Eggs of Silk-worms (one of which I have describ’d in the second _Figure_ of 25. _Scheme_) afford a pretty Object for a _Microscope_ that magnifies very much, especially if it be bright weather, and the light of a window be cast or collected on it by a deep _Convex glass_, or Water-ball. For then the whole surface of the Shell may be perceiv’d all cover’d over with exceeding small pits or cavities with interposed edges, almost in the manner of the surface of a Poppy-seed, but that these holes are not an hundredth part scarce of their bigness; the Shell, when the young ones were hatch’d (which I found an easie thing to do, if the Eggs were kept in a warm place) appear’d no thicker in proportion to its bulk, then that of an Hen’s or Goos’s Egg is to its bulk, and all the Shell appear’d very white (which seem’d to proceed from its transparency) whence all those pittings did almost vanish, so that they could not, without much difficulty, be discern’d, the inside of the Shell seem’d to be lin’d also with a kind of thin film, not unlike (keeping the proportion to its Shell) that with which the shell of an Hen-egg is lin’d; and the shell it self seem’d like common Egg-shells; very brittle, and crack’d. In divers other of these Eggs I could plainly enough, through the shell, perceive the small Insect lie coyled round the edges of the shell. The shape of the Egg it self, the Figure pretty well represents (though by default of the Graver it does not appear so rounded, and lying above the Paper, as it were, as it ought to do) that is, it was for the most part pretty oval end-ways, somewhat like an Egg, but the other way it was a little flatted on two opposite sides. Divers of these Eggs, as is common to most others, I found to be barren, or addle, for they never afforded any young ones. And those I usually found much whiter then the other that were prolifick. The Eggs of other kinds of Oviparous Insects I have found to be perfectly round every way, like so many Globules, of this sort I have observ’d some sorts of Spiders Eggs; and chancing the last Summer to inclose a very large and curiously painted Butterfly in a Box, intending to examine its gaudery with my _Microscope_, I found within a day or two after I inclos’d her, almost all the inner surface of the Box cover’d over with an infinite of exactly round Eggs, which were stuck very fast to the sides of it, and in so exactly regular and close an order, that made me call to mind my _Hypothesis_, which I had formerly thought on for the making out of all the regular Figures of Salt, which I have elsewhere hinted; for here I found all of them rang’d into a most exact _triagonal_ order, much after the manner as the _Hemispheres_ are place on the eye of a Fly; all which Eggs I found after a little time to be hatch’d, and out of them to come a multitude of small Worms, very much resembling young Silk-worms, leaving all their thin hollow shells behind them, sticking on the Box in their _triagonal_ posture; these I found with the _Microscope_ to have much such a substance as the Silk-worms Eggs, but could not perceive them pitted. And indeed, there is as great a variety in the shape of the Eggs of Oviparous Insects as among those of Birds.

Of these Eggs, a large and lusty Fly will at one time lay neer four or five hundred, so that the increase of these kind of Insects must needs be very prodigious, were they not prey’d on by multitudes of Birds, and destroy’d by Frosts and Rains; and hence ’tis those hotter Climates between the _Tropicks_ are infested with such multitudes of Locusts, and such other Vermine.

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Observ. XLII. _Of a blue _Fly_._

This kind of Fly, whereof a _Microscopical_ Picture is delineated in the first _Figure_ of the 26. _Scheme_, is a very beautifull creature, and has many things about it very notable; divers of which I have already partly describ’d, namely, the feet, wings, eyes, and head, in the preceding Observations.

And though the head before describ’d be that of a grey _Drone-Fly_, yet for the main it is very agreeable to this. The things wherein they differ most, will be easily enough found by the following particulars:

First, the clusters of eyes of this Fly, are very much smaller then those of the _Dron-Fly_, in proportion to the head.

And next, all the eyes of each cluster seem’d much of the same bigness one with another, not differing as the other, but rang’d in the same _triagonal_ order.

Thirdly, between these two clusters, there was a scaly prominent _front_ B, which was arm’d and adorn’d with large tapering sharp black brisles, which growing out in rows on either side, were so bent toward each other neer the top, as to make a kind of arched arbour of Brisles, which almost cover’d the former _front_.

Fourthly, at the end of this Arch, about the middle of the face, on a prominent part C, grew two small oblong bodies, DD, which through a _Microscope_ look’d not unlike the Pendants in Lillies, these seem’d to be jointed on to two small parts at C, each of which seem’d again jointed into the front.

Fifthly, out of the upper part and outsides of these horns (as I may call them, from the Figure they are of, in the 24. _Scheme_, where they are marked with FF) there grows a single feather, or brushy Brisle, EE, somewhat of the same kind with the tufts of a Gnat, which I have before described.

What the use of these kind of horned and tufted bodies should be, I cannot well imagine, unless they serve for smelling or hearing, though how they are adapted for either, it seems very difficult to describe: they are in almost every several kind of Flies of so various a shape; though certainly they are some very essential part of the head, and have some very notable office assign’d them by Nature, since in all Insects they are to be found in one or other form.

Sixthly, at the under part of the face FF, were several of the former sort of bended Brisles, and below all, the mouth, out of the middle of which, grew the _proboscis_ GHI, which, by means of several joints, whereof it seem’d to consist, the Fly was able to move to and fro, and thrust it in and out as it pleas’d; the end of this hollow body (which was all over cover’d with small short hairs or brisles) was, as ’twere, bent at H, and the outer or formost side of the bended part HI, slit, as it were, into two chaps, HI, HI, all the outside of which where cover’d with hairs, and pretty large brisles; these he could, like two chaps, very readily open and shut, and when he seem’d to suck any thing from the surface of a body, he would spread abroad those chaps, and apply the hollow part of them very close to it.

From either side of the _Proboscis_, within the mouth, grew two other small horns, or fingers, KK, which were hairy, but small in this Figure; but of another shape, and bigger in proportion, in the 24. _Scheme_, where they are marked with GG, which two indeed seem’d a kind of smellers, but whether so or not, I cannot positively determine.

The _Thorax_ or middle part of this Fly, was cas’d, both above and beneath, with a very firm crust of armour, the upper part more round, and covered over with long _conical_ brisles, all whose ends pointed backwards; out of the hinder and under part of this grew out in a cluster six leggs, three of which are apparent in the Figure, the other three were hid by the body plac’d in that posture. The leggs were all much of the same make, being all of them cover’d with a strong hairy scale or shel, just like the legs of a Crab or Lobster, and the contrivance of the joints seem’d much the same, each legg seem’d made up of eight parts, 1, 2, 3, 4, 5, 6, 7, 8, to the eighth or last of which, grew the soles and claws, described before in the 38. _Observation_.

Out of the upper part of this trunk grew the two wings, which I mention’d in the 38. _Observation_, consisting of a film, extended on certain small stiff wires or bones: these in a blue Fly, were much longer then the body, but in other kind of Flies they are of very differing proportions to the body. These films, in many Flies, were so thin, that, like several other plated bodies (mention’d in the ninth _Observation_) they afforded all varieties of fantastical or transient colours (the reason of which I have here endeavoured to explain) they seem’d to receive their nourishment from the stalks or wires, which seem’d to be hollow, and neer the upper part of the wing LL several of them seem’d jointed, the shape of which will sufficiently appear by the black lines in the second Figure of the 26. _Scheme_, which is a delineation of one of those wings expanded directly to the eyes.

All the hinder part of its body is cover’d with a most curious blue shining armour, looking exactly like a polish’d piece of steel brought to that blue colour by annealing, all which armour is very thick bestuck with abundance of tapering brisles, such as grow on its back, as is visible enough by the Figure.

Nor was the inside of this creature less beautifull then its outside, for cutting off a part of the belly, and then viewing it, to see if I could discover any Vessels, such as are to be found in a greater Animals, and even in Snails exceeding manifestly, I found, much beyond my expectation, that there were abundance of branchings of Milk-white vessels, no less curious then the branchings of veins and arteries in bigger terrestrial Animals, in one of which, I found two notable branches, joining their two main stocks, as it were, into one common _ductus_; now, to what veins or arteries these Vessells were _analogus_, whether to the _vena porta_, or the _meseraick vessells_, or the like, or indeed, whether they were veins and arteries, or _vasa lactea_, properly so called, I am not hitherto able to determine, having not yet made sufficient enquiry; but in all particulars, there seems not to be any thing less of curious contrivance in these Insects, then in those larger terrestrial Animals, for I had never seen any more curious branchings of Vessels, then those I observ’d in two or three of these Flies thus opened.

It is a creature active and nimble, so as there are very few creatures like it, whether bigger or smaller, in so much, that it will scape and avoid a small body, though coming on it exceeding swiftly, and if it sees any thing approaching it, which it fears, it presently squats down, as it were, that it may be the more ready for its rise.

Nor is it less hardy in the Winter, then active in the Summer, induring all the Frosts, and surviving till the next Summer, notwithstanding the bitter cold of our Climate; nay, this creature will indure to be frozen, and yet not be destroy’d, for I have taken one of them out of the Snow whereon it has been frozen almost white, with the Ice about it, and yet by thawing it gently by the warmth of a fire, it has quickly reviv’d and flown about.

This kind of Fly seems by the steams or taste of fermenting and putrifying meat (which it often kisses, as ’twere, with its _proboscis_ as it trips over it) to be stimulated or excited to eject its Eggs or Seed on it, perhaps, from the same reason as Dogs, Cats, and many other brute creatures are excited to their particular lusts, by the smell of their females, when by Nature prepared for generation; the males seeming by those kind of smells, or other incitations, to be as much necessitated thereto, as _Aqua Regis_ strongly impregnated with a solution of Gold, is forced to precipitate it by the affusion of spirit of _Urine_, or a solution of _Salt_ of _Tartar_.

One of these put in spirit of _Wine_, was very quickly seemingly kill’d, and both its eys and mouth began to look very red, but upon the taking of it out, and suffering it to lie three or four hours, and heating it with the Sun beams cast through a Burning-glass, it again reviv’d, seeming, as it were, to have been all the intermediate time, but dead drunk, and after certain hours to grow fresh again and sober.

* * * * *

Observ. XLIII. _Of the _Water Insect_ or _Gnat_._

This little creature, described in the first _Figure_ of the 27. _Scheme_, was a small scaled or crusted Animal, which I have often observ’d to be generated in Rain-water; I have also observ’d it both in Pond and River-water. It is suppos’d by some, to deduce its first original from the putrifaction of Rain-water, in which, if it have stood any time open to the air, you shall seldom miss, all the Summer long, of store of them frisking too and fro.

’Tis a creature, wholly differing in shape from any I ever observ’d; nor is its motion less strange: It has a very large head, in proportion to its body, all covered with a shell, like other _testaceous_ Animals, but it differs in this, that it has, up and down several parts of it, several tufts of hairs, or brisles, plac’d in the order express’d in the Figure; It has two horns, which seem’d almost like the horns of an Oxe, inverted, and, as neer as I could guess, were hollow, with tufts of brisles, likewise at the top; these horns they could move easily this or that way, and might, perchance, be their nostrils. It has a pretty large mouth, which seem’d contriv’d much like those of Crabs and Lobsters, by which, I have often observ’d them to feed on water, or some imperceptible nutritive substance in it.

I could perceive, through the transparent shell, while the Animal surviv’d, several motions in the head, thorax, and belly, very distinctly, of differing kinds which I may, perhaps, elsewhere endeavour more accurately to examine, and to shew of how great benefit the use of a _Microscope_ may be for the discovery of Nature’s course in the operations perform’d in Animal bodies, by which we have the opportunity of observing her through these delicate and pellucid teguments of the bodies of Insects acting according to her usual course and way, undisturbed, whereas, when we endeavour to pry into her secrets by breaking open the doors upon her, and dissecting and mangling creatures whil’st there is life yet within them, we find her indeed at work, but put into such disorder by the violence offer’d, as it may easily be imagin’d, how differing a thing we should find, if we could, as we can with a _Microscope_ in these smaller creatures, quietly peep in at the windows, without frighting her out of her usual byas.

The form of the whole creature, as it appear’d in the _Microscope_, may, without troubling you with more descriptions, be plainly enough perceiv’d by the _Scheme_, the hinder part or belly consisting of eight several jointed parts, namely, ABCDEFGH, of the first _Figure_, from the midst of each of which, on either side issued out three or four small brisles or hairs, I, I, I, I, I, the tail was divided into two parts of very differing make; one of them, namely, K, having many tufts of hair or brisles, which seem’d to serve both for the finns and tail, for the Oars and Ruder of this little creature, wherewith it was able, by frisking and bending its body nimbly to and fro, to move himself any whither, and to skull and steer himself as he pleas’d, the other part, L, seem’d to be, as ’twere, the ninth division of his belly, and had many single brisles on either side. From the end V, of which, through the whole belly, there was a kind of Gut of a darker colour, MMM, wherein, by certain _Peristaltick_ motions there was a kind of black substance mov’d upwards and downwards through it from the orbicular part of it, N, (which seem’d the _Ventricle_, or stomach) to the tail V, and so back again, which _peristaltick_ motion I have observ’d also in a Louse, a Gnat, and several other kinds of transparent body’d Flies. The _Thorax_ or chest of this creature OOOO, was thick and short, and pretty transparent, for through it I could see the white heart (which is the colour also of the bloud in these, and most other Insects) to beat, and several other kind of motions. It was bestuck and adorn’d up and down with several tufts of brisles, such as are pointed out by P, P, P, P, the head Q was likewise bestuck with several of those tufts, SSS; it was broad and short, had two black eyes, TT, which I could not perceive at all pearl’d, as they afterwards appear’d, and two small horns, RR, such as I formerly describ’d.

Both its motion and rest is very strange, and pleasant, and differing from those of most other creatures I have observ’d; for, where it ceases from moving its body, the tail of it seeming much lighter then the rest of its body, and a little lighter then the water it swims in, presently boys it up to the top of the water, where it hangs suspended with the head always downward; and like our _Antipodes_, if they do by a frisk get below that superficies, they presently ascend again unto it, if they cease moving, until they tread, as it were, under that superficies with their tails; the hanging of these in this posture, put me in mind of a certain creature I have seen in _London_, that was brought out of _America_, which would very firmly suspend it self by the tail, with the head downwards, and was said to keep in that posture, with her young ones in her false belly, which is a Purse, provided by Nature for the production, nutrition, and preservation of her young ones, which is described by _Piso_ in the 24. Chapter of the fifth Book of his Natural History of _Brasil_.

The motion of it was with the tail forwards, drawing its self backwards, by the striking to and fro of that tuft which grew out of one of the stumps of its tail. It had another motion, which was more sutable to that of other creatures, and that is, with the head forward; for by the moving of his chaps (if I may so call the parts of his mouth) it was able to move it self downwards very gently towards the bottom, and did, as ’twere, eat up its way through the water.

But that which was most observable in this creature, was, its Metamorphosis or change; for having kept several of these Animals in a Glass of Rain-water, in which they were produc’d, I found, after about a fortnight or three weeks keeping, that several of them flew away in Gnats, leaving their husks behind them in the water floating under the surface, the place where these Animals were wont to reside, whil’st they were inhabitants of the water: this made me more diligently to watch them, to see if I could find them at the time of their transformation; and not long after, I observ’d several of them to be changed into an unusual shape, wholly differing from that they were of before, their head and body being grown much bigger and deeper, but not broader, and their belly, or hinder part smaller, and coyl’d, about this great body much of the fashion represented by the prick’d line in the second _Figure_ of the 27. _Scheme_, the head and horns now swam uppermost, and the whole bulk of the body seem’d to be grown much lighter; for when by my frighting of it, it would by frisking out of its tail (in the manner express’d in the Figure by BC) sink it self below the surface towards the bottom; the body would more swiftly re-ascend, then when it was in its former shape.