 section 54 of Micrographia. This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer, please visit LibriVox.org. Micrographia by Robert Hook, section 54. Observation 49 of an Ant or Pismire. This was a creature more troublesome to be drawn than any of the rest, for I could not, for a good while, think of a way to make it suffer its body to lie quiet in a natural posture. But whilst it was alive, if its feet were fettered in wax or glue, it would so twist and wind its body that I could not any ways get a good view of it, and if I killed it, its body was so little that I did often spoil the shape of it before I could thoroughly view it. For this is the nature of these minute bodies that as soon almost as ever their life is destroyed, their parts immediately shrivel and lose their beauty. And so is it also with small plants, as I instanced before, in the description of moss, and thence also is the reason of the variations in the beards of wild oats, and in those of musk grass seed that their bodies being exceeding small, those small variations which are made in the surfaces of all bodies, almost upon every change of air, especially if the body be porous, do here become sensible where the whole body is so small that it is almost nothing but surface. For as in vegetable substances I see no great reason to think that the moisture of the air that sticking to a wreathed beard does make it on twist should evaporate or exhale away any faster than the moisture of other bodies, but rather that the avalation from, or access of moisture to, the surfaces of bodies being much the same, those bodies become most sensible of it, which have the least proportion of body to their surface. So is it also with animal substances, the dead body of an ant or such little creature does almost instantly shrivel and dry, and your object shall be quite another thing before you can have to lineate it, which proceeds not from the extraordinary exhalation, but from the small proportion of body and juices to the usual drying of bodies in the air, especially if warm, for which in convenience, where I could not otherwise remove it, I thought of this expedient. I took the creature I had designed to delineate and put it into a drop of very well rectified spirit of wine. This I found would presently dispatch, as it were, the animal, and being taken out of it and laid on a paper, the spirit of wine would immediately fly away and leave the animal dry in its natural posture, or at least in a constitution that it might easily with a pin be placed in what posture you desired to draw it, and the limbs would so remain without either moving or shriveling. Unless I dealt with this ant, which I have here delineated, which was one of many of a very large kind that inhabited under the roots of a tree, from whence they would sally out in great parties and make most grievous havoc of the flowers and fruits in the ambient garden, and return back again very expertly by the same ways and paths they went. It was more than half the bigness of an earwig, of a dark brown or reddish color with long legs on the hinder of which it would stand up and raise its head as high as it could above the ground, that it might stare the further about it just after the same manner as I have also observed a hunting spider to do. And putting my finger towards them, they have at first all run towards it till almost at it, and then they would stand around about it at a certain distance and smell as it were, and consider whether they should any of them venture any further till one more bold than the rest venturing to climate, all the rest if I would have suffered them would have immediately followed. Many such other seemingly rational actions I have observed in this little vermin with much pleasure, which would be too long to be here related, those that desire more of them may satisfy their curiosity in Liggins history of the Barbados. Having ensnared several of these into a small box, I made choice of the tallest grown among them, and separating it from the rest, I gave it a gill of brandy, or spirit of wine, which after a while Ian knocked him down dead drunk, so that he became moveless, though at first putting in he struggled for a pretty while very much, till at last certain bubbles issuing out of its mouth it ceased to move. This, because I had before found them quickly to recover again if they were taken out presently, I suffered to lie above an hour in the spirit, and after I had taken it out and put its body and legs into a natural posture, remained moveless about an hour. But then, upon a sudden, as if it had awakened out of a drunken sleep it suddenly revived and ran away. Being caught, and served as before, he for a while continued struggling and striving, till at last there issued several bubbles out of its mouth, and then, tan quam anamam experaset, he remained moveless for a good while, but at length again recovering, it was again redipped and suffered to lie some hours in the spirit. Notwithstanding which, after it had lain dry some three or four hours, it again recovered life in motion. Which kind of experiments, if prosecuted, which they highly deserve, seemed to me of no inconsiderable use towards the invention of the latent scheme, as the noble viralum calls it, or the hidden, unknown texture of bodies. Of what figure this creature appeared through the microscope, the thirty-two scheme, though not so carefully graven as it ought, will represent to the eye, namely, that it had a large head, A A, at the upper end of which were two protuberant eyes, purled like those of a fly, but smaller, B B, out of the nose, or foremost part, issued two horns, C C, of a shape sufficiently differing from those of a blue fly, though indeed they seemed to be both the same kind of organ, and to serve for a kind of smelling. Beyond these were two indented jaws, D D, which he opened sideways, and was able to gape them asunder very wide, and the ends of them being armed with teeth, which, meeting, went between each other, it was able to grasp and hold a heavy body three or four times the bulk and weight of its own body. It had only six legs shaped like those of a fly, which, as I showed before, is an argument that it is a winged insect, and though I could not perceive any sign of them in the middle part of its body, which seemed to consist of three joints or pieces E F G, out of which sprung two legs, yet T is known that there are of them that have long wings and fly up and down in the air. The third and last part of its body, I I I, was bigger and larger than the other two, unto which it was joined by a very small middle, and had a kind of loose shell, or another distinct part of its body H, which seemed to be interposed and to keep the thorax and belly from touching. The whole body was cased over with a very strong armor, and the belly I I I was covered likewise with multitudes of small white shining bristles. The legs, horns, head, and middle parts of its body were be stuck with hairs also, but smaller and darker. Section 55 of Micrographia. This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer, please visit LibriVox.org. Micrographia by Robert Hooke. Observation 50 of The Wandering Might. In September and October 1661 I observed in Oxford several of these little pretty creatures to wander to and fro, and often to travel over the plains of my window. And in September and October 1663 I observed likewise several of these very same creatures traversing a window at London, and looking without the window upon this adjacent wall, I found whole flocks of the same kind running to and fro among the small groves and thickets of green moss, and upon the curiously spreading vegetable blue or yellow moss, which is a kind of a mushroom or juicier. These creatures to the naked eye seem to be a kind of black mite, but much nimbler and stronger than the ordinary cheese mites. But examining them in a microscope I found them to be a very fine crusted or shelled insect, much like that represented in the first figure of the three-and-thirtieth scheme, with a protuberant oval shell A and then it are pitted with an abundance of small pits, all covered over with little white bristles whose points all directed backwards. It had eight legs, each of them provided with a very sharp talon or claw at the end, which this little animal in its going fastened into the pores of the body over which it went. Each of these legs were bestuck in every joint of them with multitudes of small hairs, or if we respect the proportion they bore to the bigness of the leg, turnpikes, all pointing towards the claws. The thorax or middle parts of the body of this creature was exceedingly small in respect both of the head and belly, it being nothing but that part which was covered by the two shells B.B., though it seemed to grow thicker underneath. And indeed if we consider the great variety nature uses in proportioning the three parts of the body, the head, thorax, and belly, we shall not wonder at the small proportion of this thorax nor at the vaster bulk of the belly. For could we exactly anatomize this little creature and observe the particular designs of each part? We should doubtless, as we do in all her more manageable and tractable fabrics, find much more reason to admire the excellency of her contrivance and workmanship than to wonder it was not made otherwise. The head of this little insect was shaped somewhat like a mites. That is, it had a long snout, in the manner of a hogs, with a knobbed ridge running along the middle of it, which was bestuck on either side with many small bristles all pointing forward, and two very large pikes or horns which rose from the top of the head just over each eye, and pointed forward also. It had two pretty large black eyes on either side of the head E.E., from one of which I could see a very bright reflection of the window, which made me guess that the cornea of it was smooth like those of bigger insects. Its motion was pretty quick and strong, it being able very easily to tumble a stone or clawed four times as big as its whole body. At the same time and place and diverse time since I have observed with my microscope another little insect which, though I have not annexed the picture of, may be worth noting for its exceeding nimbleness as well as smallness. It was as small as a mite with a body deep and ridged, almost like a flea. It had eight blood-red legs, not very long but slender, and two horns or feelers before. Its motion was so exceeding quick that I have often lost sight of one I have observed with my naked eye. And though when it was not frightened I was able to follow the motions of some with my microscope, yet if it were never so little startled it posted away with such speed and turned and winded itself so quick that I should presently lose sight of it. When I first observed the form of these insects or mites I began to conjecture that certainly I had found out the vagabond parents of those mites we find in cheeses, meal, corn, seeds, musty barrels, musty leather, etc. These little creatures wandering to and fro every wither might perhaps, as they were invited hither and thither by the musty steams of several putrefying bodies, make their invasions upon those new and pleasing territories, and their spending the remainder of their life which might be perhaps a day or thereabouts, in very plentiful and riotous living, might leave their offspring behind them which by the change of the soil and country they now inhabit, might be quite altered from the hue of their primogenitors, and like mores translated into northern European climates, after a little time change both their skin and shape. And this seems yet more probable in these insects because that the soil or body they inhabit seems to be almost half their parent, for it not only hatches and brings those little eggs or seminal principles to perfection, but seems to augment and nourish them also before they are hatched or shaped. For it is obvious enough to be observed that the eggs of many other insects and particularly of mites, are increased in bulk after they are laid out of the bodies of the insects, and plump sometimes and to many times their former bigness, so that the bodies that are laid in being, as it were, half their mothers. We shall not wonder that it should have such an active power to change their forms. We find by relations how much the Negro women do besmere the offspring of the Spaniard bringing forth neither white skin nor black, but tawny-heighted mulattos. Now though I propound this as probable, I have not yet been so far certified by observations, as to conclude anything either positively or negatively concerning it. Perhaps some more lucky diligence may please the curious inquirer with the discovery of this, to be a truth which I now conjecture and may thereby give him a satisfactory account of the cause of those creatures, whose original seems yet to obscure and may give him cause to believe that many other animate beings that seem also to be the mere product of putrefaction may be ennobled with a pedigree as ancient as the first creation, and far exceed the greatest beings and their numerous genealogies. But on the other side, if it should be found that these or any other animate body have no immediate similar parent, I have in another place set down a conjectural hypothesis whereby those phenomena may likely enough be solved wherein the infinite wisdom and providence of the Creator is no less rare and wonderful. Section 56 of the Crab-like Insect reading one day in September I chanced to observe a very small creature creep over the book I was reading very slowly. Having a microscope by me, I observed it to be a creature of a very unusual form, and that not less notable, such as is described in the second figure of the thirty-third scheme. It was about the bigness of a large mite, or somewhat longer. It had ten legs, eight of which, A.A.A.A., were topped with very sharp claws, and were those upon which he walked, seeming shaped much like those of a crab, which in many other things also this little creature resembled. For the two other claws, B.B., which were the foremost of all the ten and seemed to grow out of his head like the horns of other animals, were exactly formed in the manner of crabs or lobsters claws. For they were shaped and jointed much like those represented in the scheme, and the ends of them were furnished with a pair of claws, or pincers, C.C., which this little animal did open and shut at pleasure. It seemed to make use of those two horns or claws, both for feelers and holders, for in its motion it carried these aloft extended before, moving them to and fro, just as a man blindfolded would do his hands when he is fearful of running against a wall. And if I put a hair to it, it would readily take hold of it with these claws and seem to hold it fast. Now though these horns seemed to serve him for two uses, namely for feeling and holding, yet he seemed neither blind, having two small black spots, D.D., which by the make of them and the bright reflection from them seemed to be his eyes, nor did it want other hands, having another pair of claws, E.E., very near place to its mouth and seemed to joining to it. The whole body was cased over with armor shells, as is usual in all these kinds of crustaceous creatures, especially about their bellies, and seemed of three kinds. The head, F., seemed covered with a kind of scaly shell. The thorax with two smooth shells, four rings, G.G., and the belly with eight knobbed ones. I could not certainly find whether it had under these last shells any wings, but I suspect the contrary, for I have not found any winged insect with eight legs, two of those legs being always converted into wings, and for the most part, those that have but six, have wings. This creature, though I could not meet with more than one of them, and so could not make so many examinations of it as otherwise I would, I did, notwithstanding, by reason of the great curiosity that appeared to me in its shape, delineate it, to show that in all likelihood nature had crowded together into this very minute insect, as many, and its excellent contrivances, as into the body of a very large crab, which exceeds it in bulk, perhaps some millions of times. For as to all the apparent parts, there is a greater rather than a less multiplicity of parts. Each leg has as many parts and as many joints as a crabs, nay and as many hairs or bristles, and the like may be in all the other visible parts, and is very likely that the internal curiosities are not less excellent. It being a general rule in nature's proceedings that where she begins to display any excellency, if the subject be further searched into, it will manifest that there is not less curiosity in those parts which are single I cannot reach, than in those which are more obvious. End of Section 56, Recording by Philip Gould. Section 57 of Micrographia. This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer, please visit LibriVox.org. Recording by Visal. Micrographia by Robert Hooke. Section 57. Observation 52 of the small silver colored bookworm. As among greater animals, there are many that are scaled, both for ornament and defense. So are there not wanting such also among the lesser bodies of insects, whereof this little creature gives us an instance. It is a small white silver shining worm or moth, which I found much conversant among books and papers, and is supposed to be that which corrodes and eats holes through the leaves and covers. It appears to the naked eye a small glittering pearl colored moth, which upon the removing of books and papers in the summer, is often observed very nimbly to scud and pack away to some lurking cranny, where it may the better protect itself from any appearing dangers. Its head appears big and blunt, and its body tapers from it towards the tail, smaller and smaller being shaped almost like a carrot. This, the microscopical appearance, will more plainly manifest which exhibits in the third figure of the 33, scheme a conical body divided into 14 several partitions, being the appearance of so many several shells or shields that cover the whole body. Every of these shells are again covered or tiled over with a multitude of thin transparent scales, which from the multiplicity of the reflecting surfaces make the whole animal a pair of a perfect pearl color. Which, by the way, may hint us the reason of that so much admired appearance of those so highly esteemed bodies as also of the like in mother of pearl shells and in multitudes of other shelly sea substances, for they each of them consisting of an infinite number of very thin shells or laminated orbiculations cause such multitudes of reflections that the compositions of them together with the reflections of others that are so thin as to afford colors of which I elsewhere give the reason gives a very pleasant reflection of light. And that this is the true cause seems likely first because all those so appearing bodies are compounded of multitudes of plated substances and next that by ordering any transparent substance after this manner the like phenomena may be produced this will be made very obvious by the blowing of glass into exceeding thin shells and then breaking them into scales which any lamp worker will presently do. For a good quantity of these scales laid in a heap together have much the same resemblance of pearls. Another way not less instructive and pleasant is a way which I have several times done which is by working and tossing as it were. A parcel of pure crystalline glass whilst it is kept glowing hot in the blown flame of a lamp for by that means that purely transparent body will be so divided into an infinite number of plates or small shrinks with interposed aerial plates and fibers that from the multiplicity of the reflections from each of those internal surfaces it may be drawn out into curious pearl like or silver wire which though small will yet be opaque as the same thing I have done with a composition of red colophone and turpentine and a little beeswax and may be done likewise with bird line and such like glutinous and transparent bodies but to return to our description the small blunt head of this insect was furnished on either side of it with a cluster of eyes each of which seemed to contain but a very few in comparison of what I had observed the clusters of other insects to abound with. Each of these clusters were beset with a row of small bristles much like the celia or hairs on the eyelids and perhaps they served for the same purpose. It had two long horns before which were straight and tapering towards the top curiously wrinked or nobbed and bristled much like the marshweed called horsetail or cat's tail having at each knot a fringed girdle as I may so call it of smaller hairs and several bigger and larger bristles here and there dispersed among them besides these it had two shorter horns or feelers which were knotted and fringed just as the former but wanted bristles and were blunt at the ends the hinder part of the creature was terminated with three tails in every particular resembling the two longer horns that grew out of the head the legs of it were scaled and had much like the rest but are not expressed in this figure the moth being entangled all in glue and so the legs of this appeared not to the glass which looked perpendicularly upon the back. This animal probably feeds upon the paper and cowers of books and perforates in them several small round holes finding perhaps a convenient nourishment in those hulks of hemp and flax which have passed through so many scorings, washings, dressings and dryings as the parts of old paper must necessarily have suffered. The digestive faculty it seems of these little creatures being able yet further to work upon those stubborn parts and reduce them into another form and indeed when I consider what a heap of sawdust or chips this little creature which is one of the teeth of time conveys into its intervals I cannot choose but remember and admire the excellent contrivance of nature in placing in animals such a fire as is continually nourished and supplied by the materials conveyed into the stomach and fomented by the bellows of the lungs and in so contriving the most admirable fabric of animals as to make the very spending and wasting of that fire to be instrumental to the procuring and collecting more materials to augment and cherish itself which indeed seems to be the principal end of all contrivances observable in brute animals. Recordings are in the public domain for more information or to volunteer please visit LibriVox.org recording by Deon Jines Salt Lake City, Utah. Micrographia by Robert Hooke section 58 observation 53 of a flea the strength and beauty of this small creature had it no other relation at all to man would deserve a description for its strength the microscope is able to make no greater discoveries of it than the naked eye but only the curious contrivance of its legs and joints for the exerting that strength is very plainly manifested such as no other creature I have yet observed has anything like it for the joints of it are so adapted that he can as twir fold them short one within another and suddenly stretch or spring them out to their whole length that is of the forelegs the part a of the 34 scheme lies within b and b within c parallel to or side by side each other but the parts of the two next lie quite contrary that is d without e and e without f but parallel also but the parts of the hinder legs g h and i bend one within another like the parts of a double jointed ruler or like the foot leg and thigh of a man these six legs he clutches up altogether and when he leaps springs them all out and thereby exerts his whole strength at once but as for the beauty of it the microscope manifests it to be all over adorned with a curiously polished suit of sable armor neatly jointed and beset with multitudes of sharp pens shaped almost like porcupine's quills or bright conical still bodkins the head is on either side beautified with a quick and round black eye k behind each of which also appears a small cavity l in which he seems to move to and fro a certain thin film beset with many small transparent hairs which probably may be his ears in the four part of his head between the two forelegs he has two small long jointed feelers or rather smellers mm which have four joints and are hairy like those of several other creatures between these it has a small probiscus or probe n n o that seems to consist of a tube n n and a tongue or a sucker o which i have perceived him to slip in and out besides these it also has two chaps or biters p p which are somewhat like those of an ant but i could not perceive them toothed these were shaped very like the blades of a pair of round top scissors and were opened and shut just after the same manner with these instruments does this little busy creature bite and pierce the skin and suck out the blood of an animal leaving the skin inflamed with a small round red spot these parts are very difficult to be discovered because for the most part they lie covered between the four legs there are many other particulars which being more obvious and affording no great matter of information i shall pass by and refer the reader to the figure end of section 58 section 59 of micrographia this is a libravox recording all libravox recordings are in the public domain for more information or to volunteer please visit libravox.org recording by dion gines salt lake city utah micrographia by robert hook section 59 observation 54 of a louse this is a creature so officious that will be known to everyone at one time or other so busy and so impudent that it will be intruding itself in everyone's company and so proud and aspiring with all that it fears not to trample on the best and affects nothing so much as a crown feeds and lives very high and that makes it so saucy as to pull anyone by the ears that comes in its way and will never be quiet till it has drawn blood it is troubled at nothing so much as at a man that scratches his head as knowing that man is plotting and contriving some mischief against it and that makes it oftentimes skulk into some meaner and lower place and run behind a man's back though it go very much against the hair which ill conditions of it having made it better known than trusted would exempt me from making any further description of it did not my faithful mercury my microscope bring me other information of it for this has discovered to me by means of a very bright light cast on it that it is a creature of very odd shape it has a head shaped like that expressed in 35 scheme marked with a which seems almost conical but is a little flatted on the upper and under sides at the biggest part of which on either side behind the head as it were being the place where other creatures ears stand are placed its two black shining goggle eyes be be looking backwards and fenced round with several small cilia or hairs that encompass it so that it seems like this creature has no very good foresight it does not seem to have any eyelids and therefore perhaps its eyes were so placed that it might the better cleanse them with its four legs and perhaps this may be the reason why they so much avoid and run from the light behind them for being made to live in the shady and dark recesses of the hair and thence probably their eye having a great aperture the open and clear light especially that of the sun must needs very much offend them to secure these eyes from receiving any injury from the hairs through which it passes it has two horns that grow before it in the place where one would have thought the eyes should be each of these cc have four joints which are fringed as twer with small bristles from which to the tip of its snout d the head seems very round and tapering ending in a very sharp nose d which seems to have a small hole and to be the passage through which he sucks the blood now whereas if it be placed on its back with its belly upwards as it is in the thirty five scheme it seems in several positions to have a resemblance of chaps or jaws as is represented in the figure by ee yet in other postures those dark strokes disappear and having kept several of them in a box for two or three days so that for all that time they had nothing to feed on i found upon letting one creep on my hand that it immediately fell to sucking and did neither seem to thrust its nose very deep into the skin nor to open any kind of mouth but i could plainly perceive a small current of blood which came directly from its snout and passed into its belly and about a there seemed a contrivance somewhat resembling a pump pair of bellows or heart for by a very swift systole and diastole the blood seemed drawn from the nose and forced into the body it did not seem at all though i viewed it a good while as it was sucking to thrust more of its nose into the skin than the very snout d nor did it cause the least discernible pain and yet the blood seemed to run through its head very quick and freely so that it seems there is no part of the skin but the blood is dispersed into nay even into the cuticular for had it thrust its whole nose in from d to cc it would not have amounted to the proposed thickness of that segment the length of the nose being not more than a three hundredth part of an inch it has six legs covered with a very transparent shell and jointed exactly like a crabs or lobsters each leg is divided into six parts by these joints and those have here and there several small hairs and at the end of each leg it has two claws very properly adapted for its peculiar use being thereby enabled to walk very securely both on the skin and hair and indeed this contrivance of the feet is very curious and could not be made more commodiously and compendiously for performing both these requisite motions of walking and climbing up the hair of a man's head than it is for by having the lesser claw a set so much shorter of the bigger b when it walks on the skin the shorter touches not and then the feet are the same with those of a mite and several other small insects but by means of the small joints of the longer claw it can bend it round and so with both claws take hold of a hair in the manner represented in the figure the long transparent cylinder fff being a man's hair held by it the thorax seemed cased with another kind of substance than the belly namely with a thin transparent horny substance which upon the fasting of the creature did not grow flaccid through this I could plainly see the blood sucked from my hand to be variously distributed and moved to and fro and about G there seemed a pretty big white substance which seemed to be moved within its thorax besides there appeared very many small milk white vessels which crossed over the breast between the legs out of which on either side were many small branchings these seem to be the veins and arteries for that which is analogous to blood in all insects is milk white the belly is covered with a transparent substance likewise but more resembling a skin than a shell for it is grained all over the belly just like the skin in the palms of a man's hand and when the belly is empty grows very flaccid and wrinkled at the upper end of this is placed the stomach hh and perhaps also the white spot ii may be the liver or pancreas which by the peristaltic motion of the guts is a little moved to and fro not with a systole and diastole but rather with a thronging or justling motion viewing one of these creatures after it had fasted two days all the hinder part was link and flaccid and the white spot ii hardly moved most of the white branchings disappeared and most also of the redness or sucked blood in the guts the peristaltic motion of which was scarce discernible but upon the suffering it to suck it presently filled the skin of the belly and of the six scalloped embossments on either side as full as it could be stuffed the stomach and guts were as full as they could hold the peristaltic motion of the gut grew quick and the justling motion of ii accordingly multitudes of milk white vessels seemed quickly filled and turgid which were perhaps the veins and arteries and the creature was so greedy that though it could not contain more yet it continued sucking as fast as ever and as fast emptying itself behind the digestion of this creature must needs be very quick for though i perceived the blood thicker and blacker when sucked yet when in the guts it was of a very lovely ruby color and that part of it which was digested into the veins seemed white once it appears that a further digestion of blood may make it milk at least of a resembling color what is else observed in the figure of this creature may be seen by the 35 scheme end of section 59 section 60 of micrographia this is a libervox recording a libervox recordings are in the public domain for more information or to volunteer please visit libervox.org recording by dion giants salt lake city utah micrographia by robert hook section 60 observation 55 of mites the least of reptiles i have hitherto met with is a mite a creature whereof there are some so very small that the sharpest sight unassisted with glasses is not able to discern them though being white of themselves they move on a black and smooth surface and the eggs out of which these creatures seem to be hatched are yet smaller those being usually not above a four or five hundredth part of a well-grown mite and those well-grown mites not much above one hundredth of an inch in thickness so that according to this reckoning there may be no less than a million of well-grown mites contained in a cubic inch and 500 times as many eggs notwithstanding which minuteness a good microscope discovers those small movable specks to be very pretty shaped insects each of them furnished with eight well-shaped and proportioned legs which are each of them jointed or bendable in eight several places or joints each of which is covered for the most part with a very transparent shell and the lower end of the shell of each joint is fringed with several small hairs the contrivance of the joints seems the very same with that of crabs and lobster legs and like those also they are each of them terminated with a very sharp claw or point four of these legs are so placed that they seem to draw forwards the other four are placed in a quite contrary position thereby to keep the body backwards when there is occasion the body as in other larger insects consists of three regions or parts the hinder or belly a seems covered with one entire shell the middle or chest seems divided into two shells b c which running one within the other the mite is able to shrink in and thrust out as it finds occasion as it can also the snout d the whole body is pretty transparent so that being looked on against the light diverse motions within its body may be perceived as also all the parts are much more plainly delineable than in other postures to the light the shell especially that which covers the back is curiously polished so that is easy to see as in a convex looking glass or foliated glass ball the picture of all the objects round about up and down in several parts of its body it has several small long white hairs growing out of its shell which are often longer than the whole body and are represented too short in the first and second figures they seem all pretty straight and pliable save only two upon the four part of its body which seem to be the horns as may be seen in the figures the first whereof is a prospect of a smaller sort of mites which are usually more plump as it was passant to and fro the second is the prospect of one fixed on its tail by means of a little mouth glue rubbed on the object plate exhibiting the manner of the growing of the legs together with their several joints this creature is very much diversified in shape color and diverse other properties according to the nature of the substance out of which it seems to be engendered and nourished being in one substance more long in another more round in some more hairy and others more smooth in this nimble in that slow here pale and whiter there browner blacker more transparent etc i have observed it to be resident almost on all kinds of substances that are moldy or putrefying and have seen it very nimbly mushing through the thickets of mold and sometimes to lie dormant underneath them and tis not unlikely but that it may feed on that vegetating substance spontaneous vegetables seeming a food proper enough for spontaneous animals but whether indeed this creature or any other be such or not i cannot positively from any experiment or observation i have yet made determine but as i formerly hinted it seems probable that some kind of wandering might may sow as tour the first seeds or lay the first eggs in those places which nature has instructed them to know convenient for the hatching and nourishing their young and though perhaps the prime parent might be of a shape very differing from what the offspring after a little while by reason of the substance they feed on or the region as to where they inhabit yet perhaps even one of these altered progeny wandering again from its native soil and lighting on by chance the same place from once its prime parent came and their settling and planting may produce a generation of mites of the same shapes and properties with the first wandering might and from some such accidents as these i am very apt to think the most sorts of animals generally accounted spontaneous have their origination and all those various sorts of might that are to be met with up and down in diverse putrefying substances may perhaps be all of the same kind and have sprung from one and the same sort of mites at the first end of section 60 section 61 of micrographia this is a LibriVox recording a LibriVox recordings are in the public domain for more information or to volunteer please visit LibriVox.org recording by Dion Jones Salt Lake City Utah micrographia by Robert Hook section 61 observation 56 of a small creature hatched on a vine there is almost all the spring and summertime a certain small round white cobweb as twir about the bigness of a pea which sticks very close and fast to the stalks of vines nailed against a warm wall being attentively viewed they seem covered upon the upper side of them with a small husk not unlike the scale or shell of a woodlouse or hog louse a small insect usually found about rotten wood which upon touching presently rubs itself into a form of a peppercorn separating several of these from the stalk I found them with my microscope to consist of a shell which now seemed more likely to be the husk of one of these insects and the first seemed a kind of cobweb consisting of abundance of small filaments or sleeves of cobwebs in the midst of this if they were not hatched and run away before the time of which hatching was usually about the latter end of June or beginning of July I have often found abundance of small brown eggs such as A and B in the second figure of the 36 scheme much about the bigness of mites eggs and at other times multitudes of small insects shaped exactly like that in the third figure marked with 10 its head large almost half the bigness of its body which is usual in the fetus of most creatures it had two small black eyes AA and two small long jointed and bristled horns BB the hinder part of its body seemed to consist of nine scales and the last ended in a forked tail much like that of a cutio or woodlouse out of which grew two long hairs they ran to and fro very swiftly and were much of the bigness of a common mite but some of them less the longest of them seemed not the hundredth part of an inch and the eggs usually not above half as much they seemed to have six legs which were not visible in this I have here delineated by reason they were drawn under its body if these minute creatures were woodlice as indeed from their own shape and from the frame the skin or shell that grows on them one may with great probability guess it affords us an instance where of perhaps there are not many like in nature and that is of the prodigious increase of these creatures after they are hatched and run about for a common woodlouse of about half an inch long is no less than 125,000 times bigger than one of these which though indeed it seems very strange yet I have observed the young ones of some spiders have almost kept the same proportion to their dame this me thinks if it be so does in the next place hint a query which may perhaps deserve a little further examination and that is whether there be not many of those minute creatures such as mites and the like which though they are commonly thought of otherwise are only the pulley or young ones of much bigger insects and not the generating or parent insect that has laid those eggs for having many times observed those eggs which usually are found in great abundance where mites are found it seems something strange that so small an animal should have an egg so big in proportion to its body though on the other side I must confess that having kept diverse of those mites enclosed in a box for a good while I did not find them very much augmented beyond their usual bigness what the husk and cobweb of this little white substance should be I cannot imagine unless it be that the old one when impregnated with eggs should there stay and fix itself on the vine and die and all the body by degrees should rot save only the husk and the eggs in the body and the heat or fire as it were of the approaching sunbeams should vivify those relics of the corrupted parent and out of the ashes as tour as it is fabled of the phoenix should raise a new offspring for their perpetuation of the species nor will the cobweb as it were in which these eggs are enclosed make much against this conjecture for we may by those cobwebs that are carried up and down the air after fog which with my microscope I have discovered to be made up of an infinite company of small filaments or threads learn that such a texture of body may be otherwise made than by the spinning of a worm end of section 61 section 62 of micrographia this is a LibriVox recording all LibriVox recordings are in the public domain for more information or to volunteer please visit LibriVox.org recording by Dion John's Salt Lake City Utah micrographia by Robert Hook observation 57 of the eels in vinegar of these small eels which are to be found in diverse sorts of vinegar I have little to add besides their picture which you may find drawn in the third figure of the 25 scheme that is they were shaped much like an eel save only that their nose a which was a little more opacious than the rest of their body was a little sharper and longer in proportion to their body and the wriggling motion of their body seem to be only upwards and downwards whereas that of eels is only sideways they seem to have a more opacious part about b which might perhaps be their gills it's seeming always the same proportionate distant from their nose from which to the tip of their tail see their body seemed to taper taking several of these out of their pond of vinegar by the net of a small piece of filtering paper and laying them on a black smooth glass plate I found that they could wriggle and wind their body as much almost as a snake which made me doubt whether they were a kind of eel or leech I shall add no other observations made on this minute animal being prevented here in by many excellent ones already published by the ingenious dr power among his microscopical observations save only that a quantity of vinegar replete with them being included in a small vial and stopped very close from the ambient air all the included worms in a very short time died as if they had been stifled and that their motion seems contrary to what we may observe in the motion of all other insects exceedingly slow but the reason of it seems plain for it being to move to and fro after that manner which they do by waving only or wriggling their body the tenacity or glutinousness and the density or resistance of the fluid medium become so exceeding sensible to their extremely minute bodies that it is to me indeed a greater wonder that they move them so fast as they do than that they move them no faster for what a vastly greater proportion have they of their superfaces to their bulk than eels or other larger fishes and next the tenacity and density of the liquor being much the same to be moved both by the one and the other their resistance or impediment fence arising to the motions made through it must be almost infinitely greater to the small one than to the great this we find experimentally verified in the air which though a medium a thousand times more rarified than the water the resistance of it to motions made through it is yet so sensible to very minute bodies that a down feather the least of whose parts seem yet bigger than these eels and many of them almost incomparably bigger such as the quill and stock is suspended by it and carried to and fro as if it had no weight end of section 62 section 63 of micrographia this is a LibriVox recording all LibriVox recordings are in the public domain for more information or to volunteer please visit LibriVox.org micrographia by Robert Hooke observation 58 part one of a new property in the air and several other transparent mediums named inflection whereby very many considerable phenomenon are attempted to be solved and divers other uses are hinted since the invention and perfecting in some measure of telescopes it has been observed by several at the sun and moon near the horizon or disfigured losing that exactly smooth terminating circular limb which they are observed to have when situated near the zenith underbounded with an edge every way especially upon the right and left sides ragged and indented like a saw which inequality of their limbs I have further observed not to remain always the same but to be continually changed by a kind of fluctuating motion not unlike that of the waves of the sea so is that part of the limb which was but even now indented in is now protuberant and will presently be sinking again neither is this all but the whole bodies of the luminaries do in the telescope seem to be depressed and slatted the upper and more especially the underside appearing nearer to the middle than really they are and the right and left appearing more remote once the whole area seems to be terminated by a kind of oval it is further observed that the body for the most part appears red or of some color approaching nearer and to it is some kind of yellow and this I have always marked that the more the limb is slatted or ovaled the more red does the body appear though not always the contrary it is further observable that both fixed stars and planets the nearer they appear to the horizon the more red and dull they look and the more they are observed to twinkle in so much that I have seen the dog star to vibrate so strongly and bright a radiation of light as almost to dazzle my eyes and presently almost to disappear it is also observable that those bright scintillations near the horizon are not by much so quick and sudden in their consecutions of one another as the nimblest twinklings of stars nearer the zenith this is also notable that the stars near the horizon are twinkled with several colors so as sometimes to appear red sometimes more yellow and sometimes blue and this when the star is a pretty way elevated above the horizon I have further very often seen some of the small stars of the fifth or sixth magnitude at certain times to disappear for a small moment of time and again appear more conspicuous and with a greater luster I have several times with my naked eye seen many smaller stars such as maybe called of the seventh or eighth magnitude to appear for a short space and then vanish which by directing a small telescope towards that part they appeared and disappeared in I could presently find to be indeed small stars so situate as I had seen them with my naked eye and to appear twinkling like the ordinary visible stars nay in examining some very notable parts of the heaven with a three foot tube me thought I'd now and then in several parts of the constellation could perceive little twinklings of stars making a very short kind of apparition and presently vanishing but noting diligently the places where they thus seem to play at Bo Peep I made use of a very good 12 foot tube and with that it was not uneasy to see those and several other degrees of smaller stars and some smaller yet that seemed again to appear and disappear and these also by giving the same object glass a much bigger aperture I could plainly and constantly see appear in their former places so that I have observed some 12 several magnitudes of stars less than those of the six magnitudes commonly recounted in the globes it has been observed and confirmed by the accurateest observations of the best of our modern astronomers that all the luminous bodies appear above the horizon when they really are below it so that the sun and moon have both been seen above the horizon whilst the moon has been in an eclipse I shall not hear instance in the great refractions that the tops of high mountains seen at a distance have been found to have all which seem to argue the horizontal refraction much greater than it is hitherto generally believed I have further taken notice that not only the sun moon and stars and high tops of mountains have suffered these kinds of refraction but trees and several bright objects on the ground I have often taken notice of the twinkling of the reflections of the sun from a glass window at a good distance and of a candle in the night but that is not so conspicuous and in observing the setting sun I have often taken notice of the trimulation of the trees and bushes as well as of the edges of the sun divers of these phenomena have been taken notice of by several who have given several reasons of them but I have not yet met with any altogether satisfactory though some of their conjectures have been partly true but partly also false setting myself therefore upon the inquiry of these phenomena I first endeavored to be very diligent in taking notice of the several particulars and circumstances observable in them and next in making diverse particular experiments that might clear some doubts and serve to determine confirm and illustrate the true inadequate cause of each and upon the whole I find much reason to think that the true cause of all these phenomena is from the inflection or multiplicate refraction of those rays of light within the body of the atmosphere and that it does not proceed from a refraction caused by any terminating superfaces of the air above nor from any such exactly defined superfaces within the body of the atmosphere this conclusion is grounded upon these two propositions first that a medium whose parts are unequally dense and moved by various motions and transpositions as to one another will produce all those visible effects upon the rays of light without any other coefficient calls secondly that there is in the air or atmosphere such a variety in the constituent parts of it both as to their density and rarity and as to their diver's mutations and positions one to another by density and rarity I understand a property of a transparent body that is either more or less refract a ray of light coming obliquely upon its superfaces out of a third medium toward its perpendicular as I call glass a more dense body than water and water a more rare body than glass because of the refractions more or less deflecting towards the perpendicular that are made in them of a ray of light out of the air that has the same inclination upon either of their superfaces so as to the business of refraction spirit of wine is a more dense body than water it having been found by an accurate instrument that measures the angles of refractions to minutes that for the same refracted angle of 30 degrees zero minutes in both these mediums the angle of incidence and water was but 41 degrees 35 minutes but the angle of the incidence and the trial with spirit of wine was 42 degrees 45 minutes but as to gravity water is a more dense body than spirit of wine for the proportion of the same water to the same very well rectified spirit of wine was as 21 to 19 so as to refraction water is more dense than ice I have found by a most certain experiment which I exhibited before divers illustrious persons of the royal society that the refraction of water was greater than that of ice though some considerable authors have affirmed the contrary and though the ice be a very hard and the water a very fluid body that the former of the two proceeding propositions is true may be manifested by several experiments at first if you take any two liquors differing from one another in density but yet such as will readily mix as salt water or brine and fresh almost any kind of salt dissolved in water infiltrated so that it be clear spirit of wine and water nay spirit of wine and spirit of wine one more highly rectified than the other and very many other liquors if I say you take any two of these liquors and mixing them in a glass vial against one side of which you have fixed or glued a small round piece of paper and shaking them well together so that the parts of them may be seen somewhat disturbed and move up and down you endeavor to see that round piece of paper through the body of the liquors you should plainly perceive the figure to wave and to be indented much after the same manner as the limb of the sun through a telescope seems to be save only that the mutations here are much quicker and if instead of this bigger circle you take a very small spot and fasten and view it as the former you will find it to appear much like the twinkling of the stars though much quicker which two phenomena for I shall take notice of no more at present though I could instance in multitudes of others must necessarily be caused by an inflection of the race within the terminating superficies of the compounded medium since the surfaces of the transparent body through which the rays pass to the eye are not at all altered or changed this inflection if I may so call it I imagine to be nothing else but a multiplicate refraction caused by the unequal density of the constituent parts of the medium whereby the motion action or progress of the ray of life is hindered from proceeding in a straight line and inflected or deflected by a curve now that it is a curve line is manifest by this experiment I took a box such as adge in the first figure of the thirty seven scheme who sides a b c d and e f g h were made of two smooth flat plates of glass then filling it half full with a very strong solution of salt I filled the other half with very fair fresh water then exposing the opacious side d h g c to the sun I observed both the refraction and inflection of the sunbeams id and k h and marking as exactly as I could the points p n o m by which the ray k h passed through the compounded medium I found them to be in a curved line for the parts of the medium being continually more dense the nearer they were to the bottom the ray p f was continually more and more deflected downwards from the straight line this inflection may be mechanically explained either by matured to cart principles by conceiving the globules of the third element to find less and less resistance against that side of them which is downwards or by a way which I have further explicated in the inquisition about colors to be from an obligation of the pulse of light whence the under part is continually promoted and consequently refracted towards the perpendicular which cuts the orbs at right angles but the particular figure of the curve line described by this way of light is I shall not now stand to examine especially since there may be so many sorts of it as there may be varieties of the positions of the intermediate degrees of density and rarity between the bottom and the top of the inflecting medium I could produce many more examples and experiments to illustrate improve this first proposition vis that there is such a constitution of some bodies as will cause inflection as not to mention those I have observed in horn tortoise shell transparent gums and rosinous substances the veins of glass nay of melted crystal found and much complained of by glass grinders and others might sufficiently demonstrate the truth of it to any diligent observer but that I presume I have by this example given proof sufficient vis ocular demonstration to events that there is such a modulation or bending of the rays of light as I have called inflection differing from both reflection and refraction since they are both made in the superfaces this only in the middle and likewise that this is able or sufficient to produce the effects I have ascribed to it it remains therefore to show that there is such a property in the air and that it is sufficient to produce all the above mentioned phenomena and therefore may be the principal if not the only cause of them first that there is such a property may be proved from this that the parts of the air are some of them more condensed others more rarefied either by the differing heat or differing pressure it sustains or by the somewhat heterogenous vapors interspersed through it for as the air is more or less rarefied so does it more or less refract a ray of light that comes out of a denser medium from the perpendicular this you may find true if you make a trial of this experiment take a small glass bubble made in the form of that in the second figure of the thirty seven scheme and by heating the glass very hot and thereby very much rarefying the included air or which is better by rarefying a small quantity of water included in it into vapors which will expel the most part if not all the air and then sealing up the small neck of it and letting it cool you may find if you place it in a convenient instrument that there will be a manifest difference as to the refraction as if in this second figure you suppose a to represent a small cider hole through which the eye looks upon an object as see through the glass bubble B and the second side L all which remain exactly fixed in their several places the object C being so sized and placed that it may just seem to touch the upper and under edge of the whole L and so all of it be seen through the small glass ball of rarefied air then by breaking off the small sealed neck of the bubble without at all stirring the sights object or glass and admitting the external air you will find yourself unable to see the utmost ends of the object but the terminating rays A E and A D which were before refracted to G and F by the rarefied air will proceed almost directly to I and H which alteration of the rays seeing there is no other alteration made in the organ by which the experiment is tried save only the admission or exclusion of the condensed air must necessarily be caused by the variation of the medium contained in the glass B the greatest difficulty in the making of which experiment is from the uneven surfaces of the bubble which will represent an uneven image of the object now that there is such a difference of the upper and under parts of the air is clear enough events from the late improvement of the Torosellian experiment which has been tried at the tops and feet of mountains and may be further illustrated and inquired into by a means which some while since I thought of and used for the finding by what degrees the air passes from such a degree of density to such a degree of rarity and another for the finding what pressure was requisite to make it pass from such a degree of rarefaction to a determinant density which experiments because they may be useful to illustrate the present inquiry I shall briefly describe I took then a small glass pipe AB about the bigness of a swan's quill and about four foot long which was very equally drawn so that as far as I could perceive no one part was bigger than another this to being open at both ends I fitted into another small tube DE that had a small bore just big enough to contain the small pipe and this was sealed up at one and opened at the other end about which opened and I fastened a small wooden box C with cement so that filling the bigger tube in part of the box with quicksilver I could thrust the smaller tube into it till it were all covered with the quicksilver having thus done I fastened my bigger tube against the side of a wall that it might stand the steadier and plunging the small tube clear under the mercury in the box I stopped the upper end of it very fast with cement then lifting up the small tube I drew it up by a small pulley and a string that I had fastened to the top of the room and found the height of the mercurial cylinder to be about twenty nine inches then letting down the tube again I opened the top and then thrust down the small tube till I perceived the quicksilver to rise within it to a mark that I had placed just an inch from the top and immediately clapping on a small piece of cement that I had kept warm I was a hot iron sealed up the top very fast then letting it cool that both the cement might grow hard and more especially that the air might come to its temper natural for the day I tried the experiment in I observed diligently and found the included air to be exactly an inch here you are to take notice that after the air is sealed up the top of the tube is not to be elevated above the superfaces of the quicksilver in the box till the surface of that within the tube be equal to it for the quick silver as I have elsewhere proved being more heterogeneous to the glass than the air will not naturally rise up so high within the small pipe as the superfaces of the mercury in the box and therefore you are to observe how much below the outward superfaces of the mercury in the box that of the same in the tube does stand when the top being open free ingress is admitted to the outward air having thus done I permitted the cylinder or small pipe to rise out of the box till I found the surface of the quicksilver in the pipe to be two inches above that in the box and found the air to have expanded itself but one sixteenth part of an inch then drawing up the small pipe till I found the height of the quicksilver within to be four inches above that without I observed the air to be expanded only one seventh of an inch more than it was at first and to take up the room of one and one seventh inch then I raised the tube till the cylinder was six inches high and found the air to take up one and two ninths inches of room in the pipe and then to eight ten twelve et cetera the expansion of the air that I found to each of which cylinders are set down in the following table where the first row signifies the height of the mercurial cylinder the next the expansion of the air the third the pressure of the atmosphere or the highest cylinder of mercury which was then near thirty inches the last signifies the force of the air so expanded which is found by subtracting the first row of numbers out of the third for having found that the outward air would then keep up the quicksilver to thirty inches look whatever of that height is wanting must be attributed to the later of the air depressing and therefore having the expansion in the second row and the height of the subjacent cylinder of mercury in the first and the greatest height of the cylinder of mercury which of itself counterbalances the whole pressure of the atmosphere by subtracting the numbers of the first row out of the numbers of the third you will have the measure of the cylinder so depressed and consequently the force of the air in the several expansions registered table the height of the cylinder of mercury that together with the later of the included air balance the pressure of the atmosphere the expansion of the air the height of the mercury that counterbalance the atmosphere the strength of the later of the expanded air height of cylinder zero expansion of air one atmospheric pressure thirty strength of a later thirty height of cylinder two expansion of air one and one sixteenth atmospheric pressure thirty strength of a later twenty eight height of cylinder four expansion of air one and one seventh atmospheric pressure thirty strength of a later twenty six height of cylinder six expansion of air one and two ninths atmospheric pressure thirty strength of a later twenty four height of cylinder eight expansion of air one and one third atmospheric pressure 30, strength of a later 22, height of cylinder 10, expansion of air 1 and 1 half, atmospheric pressure 30, strength of a later 20, height of cylinder 12, expansion of air 1 and 2 thirds, atmospheric pressure 30, strength of a later 18, height of cylinder 14, expansion of air 1 and 5 sixth, atmospheric pressure 30, strength of a later 16, height of cylinder 16, expansion of air 2 and 2 27, atmospheric pressure 30, strength of a later 14, height of cylinder 18, expansion of air 2 and 4 ninths, atmospheric pressure 30, strength of a later 12, height of cylinder 20, expansion of air 3, atmospheric pressure 30, strength of a later 10, height of cylinder 22, expansion of air 3 and 7 ninths, atmospheric pressure 30, strength of a later 8, height of cylinder 24, expansion of air 5 and 7 eighteenths, atmospheric pressure 30, strength of a later 6, height of cylinder 25, expansion of air 6 and 2 thirds, atmospheric pressure 30, strength of a later 5, height of cylinder 26, expansion of air 8 and 1 half, atmospheric pressure 30, strength of a later 4, height of cylinder 26 and 1 quarter, expansion of air 9 and 1 half, atmospheric pressure 30, strength of a later 3 and 3 quarters, height of cylinder 26 and 1 half, expansion of air 10 and 3 quarters, atmospheric pressure 30, strength of a later 3 and 1 half, height of cylinder 26 and 3 quarters, expansion of air 13, atmospheric pressure 30, strength of a later 3 and 1 quarter, height of cylinder 27, expansion of air 15 and 1 half, atmospheric pressure 30, strength of a later 3, end of table. I had several other tables of my observations and calculations which I then made, but it being above a 12 months since I made them and by that means having forgot many circumstances and particulars I was resolved to make them over once again which I did August the 2nd, 1661 with the very same tube which I used the year before when I first made the experiment for it being a very good one I had carefully preserved it. And after having tried it over and over again and being not well satisfied of some particulars I at last having put all things in very good order and being as attentive and observant as possibly I could of every circumstance requisite to be taken notice of did register my several observations in this following table in the making of which I did not exactly follow the method that I had used at first but having lately heard of Mr. Townley's hypothesis I shaped my course in such sort as would be most convenient for the examination of that hypothesis the event of which you have in the latter part of the last table the other experiment was to find what degrees of force were requisite to compress or condense the air into such or such a bulk the manner of proceeding therein was this I took a tube about five foot long one of whose ends was sealed up and bended in the form of a siphon much like that represented in the fourth figure of the thirty seven scheme one side where of AD that was opened at a was about fifty inches long the other side BC shut it be was not much above seven inches long then placing it exactly perpendicular I poured in a little quick silver and found that the air BC was six and seven eighths inches or very near to seven then pouring in quick silver at the longer tube I continued filling of it till the air in the shorter part of it was contracted into half the former dimensions and found the height exactly nine and twenty inches and by making several other trials and several other degrees of condensation of the air I found them exactly answer the former hypothesis but having by reason it was a good while since I first made forgotten many particulars and being much unsatisfied in others I made the experiment over again and from the several trials collected the former part of the following table were in the row next to left hand twenty four signifies the dimensions of the air sustaining only the pressure of the atmosphere which at that time was equal to a cylinder of mercury of nine and twenty inches the next figure above it was the dimensions of the air and during the first compression made by a cylinder of mercury five and three sixteenths inches high to which the pressure of the atmosphere nine and twenty inches being added the elastic strength of the air so compressed will be found thirty four and three sixteenths etc. a table of the elastic power of the air both experimentally and hypothetically calculated according to its various dimensions the dimensions of the included air the height of the mercurial cylinder counter poised by the atmosphere also known as the atmospheric pressure the mercurial cylinder added or taken from the former the summer difference of these two cylinders what they ought to be according to the hypothesis the dimensions of the air twelve the atmospheric pressure twenty nine the cylinder added to the former twenty nine the sum of the two cylinders fifty eight what they ought to be fifty eight the dimensions of the air thirteen the atmospheric pressure twenty nine the cylinder added to the former twenty four and eleven sixteenths the sum of the two cylinders fifty three and eleven sixteenths what they ought to be fifty three and seven thirteenths the dimensions of the air fourteen the atmospheric pressure twenty nine the cylinder added to the former twenty and three sixteenths the sum of the two cylinders forty nine and three sixteenths what they ought to be forty nine and five sevenths the dimensions of the air sixteen the atmospheric pressure twenty nine the cylinder added to the former fourteen the sum of the two cylinders forty three what they ought to be forty three and a half the dimensions of the air eighteen the atmospheric pressure twenty nine the cylinder added to the former nine and one eighth the sum of the two cylinders thirty eight and one eighth what they ought to be thirty eight and two thirds the dimensions of the air twenty the atmospheric pressure twenty nine the cylinder added to the former five and three sixteenths the sum of the two cylinders thirty nine and three sixteenths what they ought to be thirty four and four fifths the dimensions of the air twenty four the atmospheric pressure twenty nine the cylinder added to the former zero the sum of the two cylinders twenty nine what they ought to be twenty nine the dimensions of the air forty eight the atmospheric pressure twenty nine the cylinder taken from the former fourteen and five eighths the difference of the two cylinders fourteen and three eighths what they ought to be fourteen and a half the dimensions of the air ninety six the atmospheric pressure twenty nine the cylinder taken from the former twenty two and one eighth the difference of the two cylinders six and seven eighths what they ought to be seven and two eighths the dimensions of the air one hundred ninety two the atmospheric pressure twenty nine the cylinder taken from the former twenty five and five eighths the difference of the two cylinders three and three eighths what they ought to be three and five eighths the dimensions of the air three hundred eighty four the atmospheric pressure twenty nine the cylinder taken from the former twenty seven and two eighths the difference of the two cylinders one and six eighths what they ought to be one and seven sixteenths the dimensions of the air five hundred seventy six the atmospheric pressure twenty nine the cylinder taken from the former twenty seven and seven eighths the difference of the two cylinders one and one eighth what they ought to be one and five twenty fourths the dimensions of the air seven hundred sixty eight the atmospheric pressure twenty nine the cylinder taken from the former twenty eight and one eighth the difference of the two cylinders seven eighths what they ought to be seven and one quarter eighths the dimensions of the air nine hundred sixty the atmospheric pressure twenty nine the cylinder taken from the former twenty eight and three eighths the difference of the two cylinders five eighths what they ought to be five and four fifths eighths the dimensions of the air eleven hundred fifty two the atmospheric pressure twenty nine the cylinder taken from the former twenty eight and seven sixteenths the difference of the two cylinders nine sixteenths what they ought to be ten sixteenths end of table from which experiments i think we may safely conclude that the elator of the air is reciprocal to its extension or at least very near so that to apply it to our present purpose which was indeed the chief cause of inventing these ways of trial we will suppose a cylinder indefinitely extended upwards i say a cylinder not a piece of a cone because as i may elsewhere show in the explication of gravity that triplicate proportion of the shells of a sphere to their respective diameters i supposed to be removed in this case by the decrease of the power of gravity and the pressure of the air at the bottom of this cylinder to be strong enough to keep up a cylinder of mercury of thirty inches now because by the most accurate trials of the most illustrious and incomparable mr. Boyle published in his deservedly famous pneumatic book the weight of quick silver to that of the air here below is found near about as fourteen thousand to one if we suppose that the parts of the cylinder of the atmosphere to be everywhere of an equal density we shall as he there deduces find it extended to the height of thirty five thousand feet or seven miles but because by these experiments we have somewhat confirmed the hypothesis of the reciprocal proportion of the elators to the extensions we shall find that by supposing this cylinder of the atmosphere divided into a thousand parts each of which being equivalent to thirty five feet or seven geometrical paces that is each of these divisions containing as much air as is supposed in a cylinder near the earth of equal diameter and thirty five foot high we shall find the lower most to press against the surface of the earth with the whole weight of the above mentioned the thousand parts the pressure of the bottom of the second against the top of the first to be one thousand minus one equals nine hundred ninety nine of the third against the second it would be one thousand minus two equals nine hundred ninety eight of the fourth against the third to be one thousand minus three equals nine hundred ninety seven of the uppermost against the nine hundred ninety nine or that next below it to be one thousand minus nine hundred ninety nine equals one so that the extension of the lower most next the earth will be to the extension of the next below the uppermost, as 1 to 999, for as the pressure sustained by the 999, is to the pressure sustained by the first, so is the extension of the first to the extension of the 999, so that from this hypothetical calculation we shall find the air to be indefinitely extended. For if we suppose the whole thickness of the air to be divided as I just now instanced into a thousand parts, and each of these under differing dimensions or altitudes to contain an equal quantity of air, we shall find that the first cylinder whose base is supposed to lean on the earth will be found to be extended 35 and 35999 foot. The second equal division or cylinder whose base is supposed to lean on the top of the first shall have its top extended higher by 35 and 7998, the third 35 and 105997, the fourth 35 and 140996, and so onward each equal quantity of air having its dimension measured by 35, and some additional number expressed always in the manner of a fraction, whose numerator is always the number of the place multiplied by 35, and whose denominator is always the pressure of the atmosphere sustained by that part, so that by this means we may easily calculate the height of 999 divisions of those 1000 divisions I supposed, whereas the uppermost may extend itself more than is high again, nay, perhaps indefinitely, or beyond the moon. For the elators and expansions being in reciprocal proportions, since we cannot yet find the plus ultra beyond which the air will not expand itself, we cannot determine the height of the air. For since as we have shown the proportion will be always the pressure sustained by any part is to 35, so 1000 to the expansion of that part, the multiplication or product therefore of the pressure and expansion that is of the two extreme proportionals being always equal to the product of the means or 35000, it follows since that rectangle or product may be made up of the multiplication of infinite diversities of numbers, that the height of the air is also indefinite. For since as far as I have yet been able to try, the air seems capable of an indefinite expansion, the pressure may be decreased in infinitive, and consequently its expansion upwards indefinite also. They're being therefore such a difference of density and no experiment yet known to prove assault us, or skipping from one degree of rarity to another much differing from it, that is that an upper part of the air should so much differ from that immediately subjacent to it, as to make a distinct superfaces such as we observe between the air and water, etc., but it being more likely that there is a continual increase of rarity in the parts of the air, the further they are removed from the surface of the earth. It will hence necessarily follow that as in the experiment of the salt and fresh water, the ray of light passing obliquely through the air also which is of very different density, will be continually and infinitely inflected or bended from a straight or direct motion. This granted, the reason of all the above recited phenomena concerning the appearance of the celestial bodies will very easily be deduced as first. The redness of the sun, moon and stars will be found to be caused by the inflection of the rays within the atmosphere. That it is not really in or near the luminous bodies will I suppose be very easily granted, seeing that this redness is observable in several places differing in longitude, to be at the same time different the setting and rising sun of all parts being for the most part red. And secondly, that it is not merely the color of the air interposed will I suppose without much more difficulty be yielded, seeing that we may observe a very great interstitium of air betwixt the object in the eye makes it appear of a dead blue, far enough differing from a red or yellow. But thirdly, that it proceeds from the refraction or inflection of the rays by the atmosphere, this following experiment will I suppose sufficiently manifest. Take a spherical crystalline vial such as is described in the fifth figure ABCD, and having filled it with pure clear water expose it to the sunbeams. Then taking a piece of very fine Venice paper, apply it against that side of the globe that is opposite to the sun as against the side BC. And you shall perceive a bright red ring to appear caused by the refraction of the rays AAAA, which is made by the globe. In which experiment if the glass and water be very clear so that there be no sands nor bubbles in the glass nor dirt in the water, you shall not perceive any appearance of any other color. To apply which experiment we may imagine the atmosphere to be a great transparent globe, which being of a substance more dense than the other, or which comes to the same, that has its parts more dense toward the middle, the sunbeams that are tangents or next within the tangents of this globe will be refracted or inflected from their direct passage towards the center of the globe. When it's according to the laws of refraction made in the triangular prism, and the generation of color set down in the description of Muscovy glass, there must necessarily appear a red color in the transitus or passage of those tangent rays. To make this more plain we will suppose in the sixth figure ABCD to represent the globe of the atmosphere, EFGH to represent the opacious globe of the earth lying in the midst of it, near to which the parts of the air, sustaining a very great pressure, are thereby very much condensed. From whence those rays that are by inflection made tangents to the globe of the earth, and those without them that pass through the more condensed part of the atmosphere, as supposed between A and E are by reason of the inequality of the medium, inflected towards the center whereby there must necessarily be generated a red color as is more plainly shown in the former sided place. Hence whatsoever opacious bodies as vapors or the like shall chance to be elevated into those parts will reflect a red towards the eye, and therefore these evenings and mornings appear reddest that have the most store of vapors and halitutious substances exhaled to a convenient distance from the earth, for thereby the inflection is made the greater and thereby the color also the more intense, and several of those exhalations being opacious reflect several of those rays which through inhomogeneous transparent medium would pass unseen, and therefore we see that when there are chances to be any clouds situated in those regions they reflect a strong and vivid red. Now the one great cause of the redness may be this inflection, yet I cannot wholly exclude the color of the vapors themselves which may have something of a redness in them they being partly nitrous and partly fulgenous, both which steams tinge the rays that pass through them as is made evident by looking at the bodies through the fumes of aqua fortis or spirit of nighter, as the newly mentioned illustrious person has demonstrated and also through the smoke of a fire or chimney.