 Section 9 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 Mike Botez. Micrographia by Robert Hook. Observation 6 of Small Glass Canes. That I might be satisfied whether it were not possible to make an artificial pore as small as any natural I had yet found. I made several attempts with small glass pipes melted in the flame of a lamp and then very suddenly drawn out into a great length. And by that means without much difficulty I was able to draw some almost as small as a cobweb, which yet with a microscope I could plainly perceive to be perforated. Both by looking on the ends of it and by looking on it against the light, which was much the easier way to determine whether it were solid or perforated. For taking a small pipe of glass and closing one end of it, then filling it half full of water and holding it against the light, I could by this means very easily find what was the different aspect of a solid and a perforated piece of glass. And so easily distinguish without seeing either end whether any cylinder of glass I looked on were a solid stick or a hollow cane. And by this means I could also presently judge of any small filament of glass whether it were hollow or not which would have been exceeding tedious to examine by looking on the end. And many such like ways I was feigned to make use of in the examining of divers other particulars related in this book which would have been no easy task to have determined merely by the more common way of looking on or viewing the object. For if we consider first the very faint light where with the object is enlightened when many particles appear opacus which when more enlightened appear very transparent so that I was feigned to determine its transparency by one glass and its texture by another. Next the unmanageableness of most objects by reason of their smallness. 3. The difficulty of finding the desired point and of placing it so as to reflect the light conveniently for the inquiry. Lastly one being able to view it but with one eye at once they will appear no small obstructions nor are they easily removed without many contrivances. But to proceed I could not find that water or some deeply tinged liquors would in small ones rise so high as one would expect. And the highest I have found it yet rise in any of the pipes I have tried was to 21 inches above the level of the water in the vessel. For though I found that in the small pipes it would nimbly enter at first and run about 6 or 7 inches upwards. Yet I found it then to move upwards so slow that I have not yet had the patience to observe it above that height of 21 inches and that was in a pretty large pipe in comparison of those I formerly mentioned. For I could observe the progress of a very deep tinged liquor in it with my naked eye without much trouble whereas many of the other pipes were so very small that unless in a convenient posture to the light I could not perceive them. But it is very probable that a greater patience and acidity may discover the liquors to rise. At least remain suspended at heights that I should be loath now even to guess at. If at least there be any proportion kept between the heights of the ascending liquor and the bigness of the holes of the pipes. An attempt for the explication of this experiment. My conjecture that the unequal height of the surfaces of the water preceded from the greater pressure made up on the water by the air without the pipes ABC. Then by that within them I shall endeavor to confirm from the truth of the two following propositions. The first of which is that an unequal pressure of the incumbent air will cause an unequal height in the water surfaces. And the second is that in this experiment there is such an unequal pressure that the first is true the following experiment will events. For if you take any vessel so contrived as that you can at pleasure either increase or diminish the pressure of the air upon this or that part of the surfaces of the water. The equality of the height of those parts will presently be lost. And that part of the surfaces that sustains the greater pressure will be inferior to that which undergoes the less. A fit vessel for this purpose will be an inverted glass siphon such in one as is described in the sixth figure. For if into it you put water enough to fill it as high as AB and gently blow in at D you shall depress the surfaces B. And thereby raise the opposite surfaces A to a considerable height and by gently sucking you may produce clean contrary effects. Next that there is such an unequal pressure I shall prove from this that there is a much greater incongruity of air to glass and some other bodies than there is of water to the same. By congruity I mean a property of a fluid body whereby any part of it is readily united with any other part either of itself or of any other similar fluid or solid body. And by incongruity a property of a fluid by which it is hindered from uniting with any dissimilar fluid or solid body. This last property anyone that have been observingly conversant about fluid bodies cannot be ignorant of for not now to mention several chemical spirits and oils which will very hardly if at all be brought to a mix with one another in so much that there may be found some eight or nine or more several distinct liquors which swimming one upon another will not presently mix. We need signal further for examples of this kind of fluids than to observe the drops of rain falling through the air and the bubbles of air which are by any means conveyed under the surface of the water or a drop of common salad oil swimming upon water. In all which and many more examples of this kind that might be enumerated the incongruity of two fluids is easily discernible. And as for the congruity or incongruity of liquids with several kind of firm bodies they have long since been taken notice of and called by the names of dryness and moisture. Though these two names are not comprehensive enough being commonly used to signify only the adhering or not adhering of water to some other solid bodies. Of this kind we may observe that water will more readily wet some woods than others and that water let fall upon a feather the whiter side of a call word and some other leaves or upon almost any dusty, unctuous or resinous surfaces will not at all adhere to them but easily tumble off from them like a solid bowl. Whereas if dropped upon lemon, paper, clay, green wood etc. it will not be taken off without leaving some part of it being adhering to them. So quick silver which will very hardly be brought to stick to any vegetable body will readily adhere to and mingle with several clean metaline bodies and that we may better find what the cause of congruity and incongruity in bodies is it will be requisite to consider first what is the cause of fluidness. And this I conceive to be nothing else but a certain pulse or shake of heat. For heat being nothing else but a very brisk and vehement agitation of the parts of body as I have elsewhere made probable the parts of body are thereby made so loose from one another that they easily move anyway and become fluid. That I may explain this a little by a gross similitude let us suppose a dish of sand set upon some body that is very much agitated and shaken with some quick and strong vibration motion as on a millstone turned round upon the under stone very violently whilst it is empty. Or on a very stiff drum head which is vehemently or very nimbly beaten with a drumsticks. By this means the sand in the dish which before lay like a dull and unactive body becomes a perfect fluid. And E can no sooner make a hole in it with your finger but it is immediately filled up again and the upper surface of it leveled. Nor can you bury a light body as a piece of quark under it but it presently emerges or swims as to are on top. Nor can you lay a heavier on the top of it as a piece of lead but it is immediately buried in sand and as twer sinks to the bottom. Nor can you make a hole in the side of the dish but the sand shall run out of it to a level not an obvious property of a fluid body as such but this does imitate. And all this merely caused by the vehement agitation of the containing vessel for by this means each sand becomes to have a vibrative or dancing motion so as no other heavier body can rest on it unless sustained by some other on either side. Nor will it suffer any body to be beneath it unless it be a heavier than itself. Another instance of the strange loosening nature of a violent jarring motion or a strong and nimble vibrative one we may have from a piece of iron grated on very strongly with a file. For if into that a pin screwed so firm and hard that though it has a convenient head to it yet can by no means be unscrewed by the fingers. If I say you attempt to unscrew this whilst grated on by the file it will be found to undo and turn very easily. The first of these examples manifests how a body actually divided into small parts becomes a fluid. And the latter manifests by what means the agitation of heat so easily loosens and unties the parts of solid and firm bodies nor need we suppose he to be anything else besides such motion. For supposing we could mechanically produce such a one quick and strong enough we need not spend fuel to melt a body. Now that I do not speak this altogether groundless I must refer the reader to the observations I have made upon the shining sparks of steel. For there he shall find that the same effects are produced upon small chips or parcels of steel by the flame and by a quick and violent motion. And if the body of steel may be thus melted as either shoe it may I think we have little reason to doubt that almost any other may not also. Every smith can inform one how quickly both his file and the iron grows hot with filing and if you rub almost any two hard bodies together they will do the same. And we know that a sufficient degree of heat causes fluidity in some bodies much sooner and in others later. That is the parts of the body of some are so loose from one another and so untapped to cohere and so minute and little that a very small degree of agitation keeps them always in the state of fluidity. Of this kind I suppose the ether that is the medium or fluid body in which all other bodies do as it were swim and move and particularly the air which seems nothing else but a kind of a tincture or solution of terrestrial and aqueous particle dissolved into it and agitated by it just as a tincture of cochineal is nothing but some finer dissoluble parts of that concrete licked up or dissolved by the fluid water. And from this notion of it we may easily give a more intelligible reason how the air becomes so capable of rare refaction and condensation. For as in tinctures one grain of some strongly tinging substance may sensibly color some 100,000 grains of appropriated liquors so as every drop of it has its proportion share and can be sensibly tinged as I have tried both with logwood and cochineal. And as some few grains of salt is able to infect as great a quantity as may be found by precipitations though not so easily by the site or taste. So the air which seems to be but as toward a tincture or saline substance dissolved and agitated by the fluid and agile either may disperse and expand itself into a vast space if it had room enough and infect as it were every part of that space. But as on the other side if there be but some few grains of the liquor it may extract all the color of the tinging substance and may dissolve all the salt and thereby become much more impregnated with those substances. So may all the air that suffice in a rarefied state to fill some 100,000 spaces of either be comprised in only one but in a position proportionable dense. And though we have not yet found out such strainers for tinctures and salts as we have for the air being yet unable to separate them from their dissolving liquors by any kind of filter without precipitation, as we are able to separate the air from the ether by glass and several other bodies and though we are yet unable and ignorant of the ways of precipitating air out of the ether as we can tinctures and salts out of several dissolvings. Yet neither of these seeming impossible from the nature of things nor so improbable but that some happy future industry may find out ways to effect them. Nay further since we find that nature does really perform though by what means we are not certain both these actions namely by precipitating the air in rain and dews and by supplying the streams and rivers of the world with fresh water strained through secret subterranean coverns and since that in very many other properties they do so exactly seem of the same nature till further observations or trials do inform us of the contrary we may safely enough conclude them of the same kind for it seldom happens that any two natures have so many properties coincident or the same as I have observed solutions and air to have and to be different in the rest and therefore I think it neither impossible, irrational, nane or difficult to be able to predict what is likely to happen in other particulars also besides those which observation or experiment have declared thus or thus especially if the circumstances that do often very much conduce to the variation of the effects by duly weighed and considered and indeed were there not a probability of this our enquiries would be endless our trials vain and our greatest inventions would be nothing but the mere products of chance and not of reason and like mariners in an ocean destitute both of a compass and the site of the celestial guides we might indeed by chance steer directly towards our desired port but it is a thousand to one but we miss our aim but to proceed we may hence also give a plain reason how the air comes to be darkened by the clouds and etc which are nothing but a kind of precipitation and how those precipitations fall down in showers hence also could I very easily and I think truly deduce the cause of the curious sigsangular figures of snow and the appearance of hollows etc and the sudden thickening of the sky with clouds and the vanishing and disappearing of those clouds again for all these things may be very easily imitated in a glass of liquor with some slight chemical preparations as I have often tried and may somewhere else more largely relate but have not no time to set them down but to proceed there are other bodies that consist of particle more gross and of a more apt figure for cohesion and this requires somewhat greater agitation such I suppose mercury fermented venous spirits several chemical oils which are much of a kin to those spirits and cera others yet require a greater as water and so others much greater for almost infinite degrees for I suppose there are very few bodies in the world that may not be made aliquotonous fluid by some or other degree of agitation or heat having therefore in short set down my notion of a fluid body I come in the next place to consider what congruity is and this as I said before being a relative property of a fluid whereby it may be said to be like or unlike to this or that other body whereby it does or does not mix with this or that body we will again have recourse to our former experiment though but rude one and here if we mix in the dish several kinds of sands some of bigger other of less and finer box we shall find that by the agitation the fine sand will eject and throw out of itself all those bigger box of small stones and the like and those will be gathered together all into one place and if there be other bodies in it of other natures those also will be separated into a place by themselves and united or tumbled up together and though this do not come up to the highest property of congruity which is a cohesion of the parts of the fluid together or a kind of attraction and tenacity yet this does as to our shadow it out and somewhat resemble it for just after the same manner I suppose the pulse of heat to agitate the small parcels of matter and those that are of a like bigness and figure and matter will hold or dance together and those which are of a differing kind will be thrust or shoved out from between them for particles that are similar will like so many equal musical strings equally stretch vibrate together in a kind of harmony or unison whereas others that are dissimilar upon what account so ever unless the disproportion be otherwise counter balanced will like so many strings out of tune to those unisons though they have the same agitating pulse yet may quite differing kinds of vibrations and repercussions so that though they may be both moved yet are their vibration so different and so untuned as toward to each other that they cross and jar against each other and consequently cannot agree together but fly back from each other to their similar particles now to give you an instance how the disproportion of some bodies in one respect may be counter balanced by contrary disproportion of the same body in another respect once we find that the subtle venous spirit is congruous or does readily mix with water which in many properties is of a very different nature we may consider that a unison may be made either by two strings of the same bigness length and tension or by two strings of the same bigness but of differing length and a contrary differing tension or thirdly by two strings of unequal length and bigness and of a different tension or of equal length and differing bigness and tension and several other such varieties to which three properties in strings will correspond three properties also in sand or the particles of bodies their matter or substance their figure or shape and their body or bulk and from the varieties of these three may arise infinite varieties in fluid bodies though all agitated by the same pulse or vibrative motion and there may be as many ways of making harmonies and discords with these as there may be with musical strings having therefore seen what is the cause of congruity or incongruity those relative properties of fluids we may from what has been said very easily collect what is the reason of those relative properties also between fluid bodies and solid for since all bodies consist of particles of such a substance figure and bulk but in some they are united together more firmly than to be loosened from each other by every vibrative motion though I imagine that there is no body in the world but that some degree of agitation may as I hinted before agitate and loosen the particles so as to make them fluid those cohering particles may vibrate in the same manner almost as those that are loose and become unisons or discords as I may so speak to them now that the parts of all bodies though never so solid do yet vibrate I think we need go no further for proof than that all bodies have some degree of heating them and that there has not been yet found anything perfectly cold nor can I believe indeed that there is any such thing in nature as a body whose particles are at rest or lazy and unactive in the great theater of the world it being quite contrary to the grand economy of the universe we see therefore what is the reason of the sympathy or uniting of some bodies together and of the antipathy or flight of others from each other for congruity seems nothing else but a sympathy and incongruity an antipathy of the bodies hence similar bodies once united will not easily part and dissimilar bodies once disjoined will not easily unite again from hands may be very easily deducted the reason of the suspension of water and quick silver above their usual station as I shall more at large a non shoe these properties therefore always the concomitants of fluid bodies produce these following visible effects first they unite the parts of a fluid to its similar solid or keep them separate from its dissimilar hence quick silver will as we noted before stick to gold silver tin lead and cetera and unite with them but roll off from wood stone glass and cetera if never so little situated out of its horizontal level and water that will wet salt and dissolve it will slip off from tallow or the like without at all adhering as it may likewise be observed to do upon a dusty surfaces and next they cause the parts of homogenial fluid bodies readily to adhere together and mix and of heterogeneous to be exceeding a verse they run to hence we find that two small drops of water on any surfaces they can roll on well if they chance to touch each other readily unite and mix into a third drop the like may be observed with two small bowls of quick silver upon a table or glass provided their surfaces be not dusty and with two drops of oil upon fair water and cetera and further water put unto wine saltwater vinegar spirit of wine or the like does immediately especially if they be shaken together disperse itself all over them hence on the contrary we also find that oil of tartar poured upon quick silver and spirit of wine on that oil and oil of turpentine on that spirit and air upon that oil though they be stopped closely up into a bottle and shaken never so much they will by no means long suffer any of their bigger parts to be united or included within any of the other liquors by which recited liquors may be plainly enough represented by the four peripatetical elements and the more subtle ether above all from this property tears that a drop of water does not mingle with or vanish into air but is driven by that fluid equally protruding it on every side and forced into as little a space as it can possibly be contained in namely into a round globule so likewise a little air blown under the water is united or thrust into a bubble by the ambient water and a parcel of quick silver enclosed with air water or almost any other liquor is formed into a round ball now the cause why all these included fluids newly mentioned or as many others as are wholly included within a heterogeneous fluid are not exactly of a spherical figure seeing that if caused by these principles only it could be of no other must proceed from some other kind of pressure against the two opposite flatted sides disadvantageous were accidental pressure may proceed from diverse causes and accordingly must diversify the figure of the included heterogeneous fluid for seeing that a body may be included either with a fluid only or only with a solid or partly with a fluid and partly with a solid or partly with one fluid and partly with another there will be found a very great variety of the terminating surfaces much differing from a spherical according to the various resistance or pressure that belongs to each of these encompassing bodies which properties may in general be deduced from two heads vis-à-vis motion and rest for either this globular figure is altered by a natural motion such as his gravity or a violent such as is any accidental motion of the fluids as we see in the wind ruffling up the water and the purlings of streams and foaming of cataracts and the like or thirdly by the rest firmness and stability of the ambient solid for if the including solid be of an angular or any other irregular form the included fluid will be near of the like as a pint pot full of water or a bladder full of air and next if the including or included fluid have a greater gravity one than another then will the globular form be depressed into an elliptic or spherical as if for example we suppose the circle ABCD in the fourth figure to represent a drop of water quick silver or the like included with the air or the like which supposing there were no gravity at all in either of the fluids or that the contained and containing were of the same weight would be equally compressed into an exactly spherical body the ambient fluid forcing equally against every side of it but supposing either a greater gravity in the included by reason were of the parts of it being pressed from a towards B and thereby the whole put into motion and that motion being hindered by the resistance of the subjacent parts of the ambient the globular figure ADBC will be depressed into the elliptic or spherical EGF H for the side A is detruded to E by the gravity and B to F by the resistance of subjacent medium and therefore C must necessarily be thrust to G and D to H or else supporting a greater gravity in the ambient by who's more than ordinary pressure against the underside of the included globule B will be forced to F and by its resistance of the motion upwards the side A will be depressed to E and therefore C be in thrust to G and D to H the globular figure by this means also will be made an elliptical spherical next if a fluid be included partly with one and partly with another fluid it will be found to be shaped diversely according to the proportion of the gravity and incongruity of the three fluids one to another as in the second figure let the upper MMM by air the middle LMNO by common oil the lower OOO by water the oil will be formed not into a spherical figure such as is represented by the prect line but into such a figure as LMNO whose side LMN will be of a flatter elliptical figure by reason of the great disproportion between the gravity of oil and air and the side LOM of a rounder because of the smaller difference between the weight of oil and water lastly the globular figure will be changed if the ambient be partly fluid and partly solid and here determination of the encompassed fluid towards the encompassing is shaped according to the proportion of the congruity or incongruity of the fluids to the solids and of the gravity and incongruity of the fluids one to another as suppose the subjacent medium that hinders an included fluids descent be a solid as let Ki in the fourth figure represent the smooth surfaces of a table EGFH a parcel of running mercury the side GFH will be more flatted according to the proportion of the incongruity of the mercury and air to the wood and of the gravity of the mercury and air one to another the side GFH will likewise be a little more depressed by reason the subjacent parts are now at rest which were before in motion or further in the third figure let AI LD represent an including solid medium of a cylindrical shape as suppose a small glass jar let FGE MM represent a contained fluid as water this towards the bottom and sides is figured according to the concavity of the glass but its upper surface which by reason of its gravity not considering at all the air above it and so neither the congruity or incongruity of either of them to the glass should be terminated by part of a sphere whose diameter should be the same with that of the earth which to our sense would appear a straight line as FGE or which by reason of its having a greater congruity to glass than air has not considering its gravity would be thrust into a concave sphere as CHB whose diameter would be the same with that of the concavity of the vessel its upper surface I say by reason of its having a greater gravity than the air and having likewise a greater congruity to glass than the air has is terminated by a concave elliptic was spherical figure as CKB for by its congruity it easily conforms itself and adheres to the glass and constitutes as it were one containing body with it and therefore should thrust the contained air on that side it touches it into a spherical figure as BHC but the motion of gravity depressing a little the corners B and C reduces it into the aforesaid figure CKB now that it is the greater congruity of one of the two contiguous fluids than of the other to the containing solid that causes a separating surfaces to be thus or thus figured and that it is not because this or that figurative surface is more proper natural or peculiar to one of these fluid bodies than to the other will appear from this that the same fluids will by being put into differing solids change their surfaces for the same water which in a glass or wooden vessel will have a concave surface upwards and will rise higher in a smaller than a greater pipe the same water I say in the same pipes greased over or oiled will produce quite contrary effects for it will have a protuberant and convex surface upwards and will not rise so high and small as in bigger pipes may in the very same solid vessel you may make the very same two contiguous liquids to alter their surfaces for taking a small wine glass or such like vessel and pouring water gently into it you shall perceive the surface of the water all the way concave till its rise even with the top when you shall find it if you gently and carefully pour in more to grow very protuberant and convex the reason of which is plain for that the solid sides of the containing body are no longer extended to which the water does more readily adhere than the air but it is henceforth to be included with air which would reduce it into a hemisphere but by reason of its gravity it is flatted into a novel quick silver also which the glass is more incongruous than air and thereby being put into a glass pipe will not adhere to it but by the more congruent air will be forced to have a very protuberant surface and to rise higher in a greater than a lesser pipe this quick silver to clean metal especially to gold silver tin lead and terror iron accepted is more congruent than air and will not only stick to it but have a concave surface like water and rise higher in a less than in a greater pipe in all these examples it is evident that there is an extraordinary and advantageous force by which the globular figure of the contained heterogeneous fluid is altered neither can it be imagined how it should otherwise be of any other figure than globular for being by the heterogeneous fluid equally protruded every way whatsoever part is protuberant will be thereby depressed from this cause it is that in its effects it does very much resemble a round spring such as a hoop for as in a round spring there is required an additional pressure against two opposite sides to reduce it into an oval form or to force it in between the sides of a hole whose diameter is less than that of a spring there must be a considerable force of protrusion against the concave or inner side of the spring so to alter this spherical constitution of an included fluid body there is required more pressure against opposite sides to reduce it into an oval and to press it into a hole less in diameter than itself it requires a greater protrusion against all the other sides what degrees of force are requisite to reduce them into longer and longer ovals or press them into less and less holes I have not yet experimentally calculated but thus much by experiment I find in general that there is always required a greater pressure to close them into longer ovals or protrude them into smaller holes the necessity and reason of this were its requisite I could easily explain but being not so necessary and requiring more room and time than I have for it at present I shall hear omitted and proceed to shoe that this may be presently found true if experiment be made with a round spring the way of making which trials is obvious enough and with fluid bodies of mercury, air and cera the way of trying which will be somewhat more difficult and therefore I shall in brief describe it he therefore that would try with air must first be provided of a glass pipe made of the shape of that in the fifth figure where off the side AB represents a straight tube of about three foot long C represents another part of it which consists of a round bubble so ordered that there is left a passage or a hole at the top into which may be fastened with cement several small pipes of determinate cylindrical cavities as let hollow of F be one quarter of an inch G one six H one eighth I one twelve K one sixteenth L one twenty fourth M one thirty two and cetera there may be added as many more as the experimenter shall think fit with holes continually decreasing by known quantities so far as his senses are able to help him I say so far because there may be made pipes so small that it will be impossible to perceive the perforation with one's naked eye though by the help of a microscope it may easily enough be perceived may I have made a pipe perforated from end to end so small that with my naked eye I could very hardly see the body of it in so much that I have been able to need it up into a knot without breaking and more accurately examining one with my microscope I found it not so big as a sixteenth part of one of my smaller hairs of my head which was of the smaller and finer sort of hair so that sixteen of these pipes bound faggot wise together would but have equalized one single hair how small therefore must its perforation be it appears to me through the microscope to be a proportionably thick-sided pipe to proceed then for the trial of the experiment the experimenter must place the tube AB perpendicular and fill the pipe F cemented into the whole E with water but leave the bubble C full of air and then gently pouring in water into the pipe AB he must observe diligently how high the water will rise in it before it protrude the bubble of air C through the narrow passage of F and denote exactly the height of the cylinder of the water then cementing in a second pipe as G and filling it with water he may proceed as with the former denoting likewise the height of the cylinder of water able to protrude the bubble C through the passage of G the like may he do with the next pipe and the next and etc as far as he is able then comparing the several heights of the cylinders with the several holes through which each cylinder did force the air having due regard to the cylinder of water in the small tubes it will be very easy to determine what forces requisite to press the air into such and such a hole or to apply it to our present experiment how much of the pressure of the air is taken off by its ingress into smaller and smaller holes from the application of which to the entering of the air into the bigger hole of the vessel and into the smaller hole of the pipe we shall clearly find that there is a greater pressure of the air upon the water in the vessel or greater pipe than there is upon that in the lesser pipe for since the pressure of the air every way is found to be equal that is as much as he is able to press up and sustain a cylinder of quicksilver of two foot and a half high or thereabouts and since of this pressure so many more degrees are required to force the air into a smaller than into a greater hole that is full of a more congruous fluid and lastly since those degrees that are requisite to press it in are thereby taken off from the air within and the air within left with so many degrees of pressure less than the air without it will follow that the air in the less tube or pipe will have less pressure against the surface of the water therein than the air in the bigger which was the minor proposition to be proved the conclusion therefore will necessary follow vis-à-vis that this unequal pressure of the air caused by its ingress into unequal holes is a cause sufficient to produce this effect without the help of any other concurrent therefore is probably the principle if not the only cause of this phenomena and of section 9 recording by Mike Botez section 10 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 Mike Botez micrographia by Robert Hook observation 6 of small glass canes part 2 this therefore be and thus explained there will be diverse phenomena explicable thereby as the rising of liquors in a filter the rising of spirit of wine, oil, melted tallow, etc. in the weak of a lamp, though made of small wire, threads of asbestos, strings of glass or the like the rising of liquors in a sponge, piece of bread, sand and tera perhaps also the ascending of the sap in trees and plants through their small and some of them imperceptible pores of which I have said more on another occasion at least the passing of it out of the earth into their roots and indeed upon the consideration of this principle multitudes of other uses of it occur to me which I have not yet so well examined and digested as to per pound for axioms but only as queries and conjectures which may serve as hands towards some further discoveries as first upon the consideration of the congruity and incongruity of bodies as to touch I found also the like congruity and incongruity if I may so speak as to the transmitting of the rates of light for as in this regard water not now to mention other liquors seems nearer of affinity to glass than air and air than quick silver whence an oblique ray out of glass will pass into water with very little refraction from the perpendicular but none out of glass into air except direct will pass without a very great refraction from the perpendicular nay any oblique ray under 30 degrees will not be admitted into the air at all and quick silver will neither admit oblique or direct but reflects all seeming as to the transmitting of the rays of light to be of a quite differing constitution from that of air, water, glass etc. and to resemble most those opaque and strong reflecting bodies of metals so also as to the property of cohesion or congruity water seems to keep the same order being more congruous to glass than air and air than quick silver a second thing which was hinted to me by the consideration of the included fluids globular form caused by the protrusion of the ambient heterogeneous fluid was whether the phenomena of gravity might not by this means be explained by supposing the globe of earth, water and air to be included with a fluid heterogeneous to all and each of them so subtle as not only to be everywhere interspersed through the air or rather the air through it but to pervade the bodies of glass and even the closest metals by which means it may endeavor to detrude all earthly bodies as far from it as it can and partly thereby and partly by other of its properties may move them towards the center of the earth now that there is some such fluid I could produce many experiments and reasons that do seem to prove it but because it would ask some time and room to set them down and explain them and to consider and answer all the objections many whereof I foresee that may be alleged against it I shall at present proceed to other queries containing myself to have here only given a hint of what I may say more elsewhere a third query than was whether the heterogeneity of the ambient fluid may not be accounted a secondary cause of the roundness or globular form of the greater bodies of the world such as are those of the sun stars and planets the substance of each of which seems altogether heterogeneous to the circumambient fluid ether and of this I shall say more in the observation of the moon a fourth was whether the globular form of the smaller parcels of matter here upon the earth as that of fruits pebbles or flints and cetera which seem to have been a liquor at first may not be caused by the heterogeneous ambient fluid for thus we see that melted glass will be naturally formed into a round figure so likewise any small parcel of any fusible body if it be perfectly enclosed by the air will be driven into a globular form and when cold will be found a solid ball this is plainly enough manifested to us by their way of making shot with the drops of lead which being a very pretty curiosity and known but very few and having the liberty of publishing it granted to me by that eminent virtuoso Sir Robert Moray who brought in this account of it to the Royal Society I have here transcribed and inserted to make small shot of different sizes communicated by his highness PR take lead out of the pig what quantity please melt it down stir and clear it with an iron ladle gathering together the blackish parts that swim at top like scrum and when you see the color of the clear lead to be greenish but no sooner through up on it or a pigment powdered according to the quantity of lead about as much as will lie up on a half crown piece will serve for 18 or 20 pound weight of some sorts of lead others will require more or less after the ory pigmentum is put in stir the lead well and the ory pigmentum will flame when the flame is over take out some of the lead in a ladle having a lip or notch in the brim for convenient pouring out of the lead and being well warmed amongst the melted lead and with a stick make some single drops of lead trickle out of the ladle into water in a glass which if they fall to be around and without tails there is ory pigmentum enough to put in it and the temper of the heat is right otherwise put in more then lay two bars of iron or some more proper iron tool made on purpose upon a pail of water and place upon them a round plate of copper of the size and figure of an ordinary large pewter or silver trencher the hollow where off is to be about 3 inches over the bottom lower than the brims about half an inch pierced with 30, 40 or more small holes the smaller the holes are the smaller the shot will be and the brim is to be thicker than the bottom to conserve the heat the better the bottom of the trencher being some 4 inches distant from the water in the pail lay upon it some burning coals to keep the lead melted upon it then with a hot ladle take lead off the pot where it stands melted and pour it softly upon the burning coals over the bottom of the trencher and it will immediately run through the holes into the water in small round drops thus pour on new lead as fast as it runs through the trencher till all be done blowing now and then the coals with hand bellows when the lead in the trencher cools so as to stop from running while one pours on the lead another must with another ladle thrusted 4 or 5 inches under water in the pail catch from time to time some of the shot as it drops down to see the size of it and whether there be any fault in it the greatest care is to keep the lead up on the trencher in the right degree of heat if it be too cool it will not run through the trencher though it stand melted upon it and this is to be helped by blowing the coals a little or pouring on new lead that is hotter but the cooler the lead the larger the shot and the hotter the smaller when it is too hot the drops will crack and fly then you must stop pouring on new lead and let it cool and so long as you observe the right temper of the heat the lead will constantly drop into very round shot without so much as one with a tail in many pounds when all is done take your shot out of the pail of water and put it in a frying pan over the fire to dry them which must be done warily still shaking them that they melt not and when they are dry you may separate the small from the great in pearl sieves made of copper or Latin let into one another into as many sizes as you please but if you would have your shot larger than the trencher makes them you may do it with a stick making them trickle out of the ladle as have been said if the trencher be but touched very little when the lead stops from going through it and be not too cool it will drop again but it better not touch it at all but the melting of the lead take care that there be no kind of oil crease or the like upon the pots or ladles or trencher the chief cause of this globular figure of the shot seems to be the ori pigmentum for as soon as it is put in among the melted lead it loses its shining brightness contracting instantly a grayish film or skin upon it when you scum it to make it clean with a ladle so that when the air comes at the falling drop of the melted lead that skin constricts them everywhere equally but upon what account and whether this be the true case is left to further disquisition much after the same manner when the air is exceeding cold through which it passes do we find the drops of rain falling from the clouds congealed into around hail stones by the freezing ambient to which may be added the other known experiment that if you gently let fall a drop of water upon small sand or dust you shall find as it were an artificial round stone quickly generated I cannot upon this occasion omit the mentioning of the strange kind of grain which I have observed in a stone brought from Kettering in Northamptonshire and therefore called by Mason's Kettering stone of which see the description which brings into my mind what I long since observed in the fiery sparks that are struck out of a steel for having a great desire to see what was left behind after the spark was gone out I purposely struck fire over a very white piece of paper and observing diligently where some conspicuous sparks went out I found a very little black spot no bigger than the point of a pin which through a microscope appear to be a perfectly round ball looking much like a polished ball of steel in so much that I was able to see the image of the window reflected from it I cannot here stay having done it more fully in another place to examine the particular reasons of it but shall only hint that I imagine it to be some small parcel of the steel which by the violence of the motion of the stroke most of which seems to be impressed upon those small parcels is made so glowing hot that it is melted into a vitrum which by the ambient air is thrust into the form of a ball a fifth thing which I thought worth examination was whether the motion of all kind of springs might not be reduced to the principle whereby the included heterogeneous fluid seems to be moved or to that whereby two solids as marbles or the like are thrust and kept together by the ambient fluid a sixth thing was whether the rising and abolition of the water out of springs and fountains which lie much higher from the center of the earth than the superfaces of the sea from whence it seems to be derived may not be explicated by the rising of water in smaller pipe for the sea water being strained through the pores or crannies of the earth is as it were included in little pipes where the pressure of the air has not so great a power to resist its rising but examine in this way and finding in it several difficulties almost irremovable I thought up on a way that would much more naturally and conceivably explain it which was by this following experiment I took a glass tube of the form of that described in the sixth figure and choosing two heterogeneous fluids such as water and oil I poured in as much water as filled up the pipes as high as AB then putting in some oil into the tube AC I depressed the superfaces A of the water to F and B I raised to G which was not so high perpendicularly as the superfaces of the oil F by the space F I where for the proportion of the gravity of these two liquors was as G H to F E this experiment I tried with several other liquors and particularly with fresh water and salt which I made by dissolving salt in warm water which too though there are nothing heterogeneous yet before they would perfectly mix one with another I made trial of the experiment nay letting the tube wear in I tried the experiment remain for many days I observed them not to mix but the superfaces of the fresh was rather more than less elevated above that of the salt now the proportion of the gravity of seawater to that of river water according to Stevinus and Varanus and as I have since found pretty true by making trial myself is as 46 to 45 that is 46 ounces of the salt water will take up no more room than 45 of the fresh or reciprocally 45 pints of salt water weighs much as 46 of fresh but I found the proportion of brine to freshwater to be a near 13 to 12 supposing therefore G H M to represent the sea and F I the height of the mountain above the superfaces of the sea F M a cover in the earth beginning at the bottom of the sea and terminated at the top of the mountain L M the sand at the bottom through which the water is as it were strained so as that the fresher parts are only permitted to transude and the saline kept back if therefore the proportion of G M to F M be as 45 to 46 then may the cylinder of salt water G M make the cylinder of freshwater to rise as high as E and to run over at N I cannot here stand to examine or confute their opinion who make the depth of the sea below its purposes to be no more perpendicularly measured than the height of the mountains above it it is enough for me to say there is no one of those that have asserted it have experimentally known the perpendicular of either nor shall I here determine whether there may not be many other causes of separation of the fresh water from the salt as perhaps some parts of the earth through which it is to pass may contain salt that mixing and uniting with sea salt may precipitated much after the same manner as the alkalisate and acid salts mix and precipitate each other in the preparation of tartarum vitriolatum I know not also whether the exceeding cold that must necessarily be at the bottom of the water may not help towards this separation for we find that warm water is able to dissolve and contain more salt than the same cold in so much that brines strongly impregnated by heat if let cool do suffer much of their salt to subside and crystallize about the bottom and sides I know not also whether the exceeding pressure of the parts of the water one against another may not keep the salt from descending to the very bottom as finding little or no room to insert itself between those parts protruded so violently together or else squeeze it upwards into the superior parts of the sea where it may more easily obtain room for itself amongst the parts of the water by reason that there is more heat and less pressure to this opinion I was somewhat the more induced by the relations I have met with in geographical writers of drawing fresh water from the bottom of the sea which is salt above I cannot now stand to examine whether this natural perpetual motion may not artificially be imitated nor can I stand to answer the objections which may be made against this my supposition as first how it come to pass that there are sometimes salt springs much higher than the superfaces of the water and secondly why springs do not run faster and slower according to the varying height made of the cylinder of sea water by the ebbing and flowing of the sea as to the first in short I say the fresh water may receive again a saline tincture near the superfaces of the earth by passing through some salt mines or else many of the saline parts of the sea may be kept back though not all and as to the second the same spring may be fed and supplied by diverse caverns coming from very far distant parts of the sea so as that it may in one place be high in another low water and so by that means the spring may be equally supplied at all times or else the cavern may be so straight and narrow that the water not having so ready and free passage through it cannot upon so short and quick mutations of pressure to be able to produce any sensible effect at such a distance besides that to confirm this hypothesis there are many examples found in natural historians of springs that do ebb and flow like the sea as particularly those recorded by the learned Camden and after him by speed to be found in this island one of which they relate to be on the top of a mountain by the small village Kilken in Flintshire Maris emulus quistatis temporibus suos evomet et resorbet aquas which at certain times riseth and falleth after the manner of the sea a second in Carmarthenshire near Carmarthen at a place called country's bishan qui would scribit geraldus naturali die bis undis deficiens et toties exuberans marinas imitatur instabilitatis that twice in four and twenty hours ebbing and flowing ressembleth the unstable motions of the sea the phenomena of which two may be easily made out by supposing the cavern by which they are fed to arise from the bottom of the next sea a third is a well upon the river Ogmore in Glamorganshire and near Anton Newton of which Camden relates himself to be certified by a letter from a learned friend of his that observed it fonts abest hink and et cetera the letter is a little too long to be inserted but the substance is this that this well ebbs and flows quite contrary to the flowing and ebbing of the sea in those parts for it is almost empty at full sea but full at low water this may happen from the channel by which it is supplied which may come from the bottom of the sea very remote from those parts and where the tides are much differing from those of the approximate shores a fourth lies in Westmoreland near the river Leather which in star Eurypicepius india rich procantibus undis fluid et refluid which ebbs and flows many times a day this may proceed from its being supplied from many channels coming from several parts of the sea lying sufficiently distance asunder to have the times of high water differing enough one from the other so as that when so ever it shall be high water over any of those places where these channels begin it shall likewise be so in the well but this is but a supposition a seventh query was whether the dissolution or mixing of several bodies whether fluid or solid with saline or other liquors might not partly be attributed to this principle of the congruity of those bodies and their dissolvents as of salt in water, metals in several man's thrones, unctuous gums in oils, the mixing of wine and water, etc. and whether precipitation be not partly made from the same principle of incongruity I say partly because there are in some dissolutions some other causes concurrent I shall lastly make a much more seemingly strange and unlikely query and that is whether this principle well examined and explained may not be found a coefficient in the most considerable operations of nature as in those of heat and light consequently of refraction and condensation, hardness and fluidness, perspicuity and opaqueness, refractions and colors, etc. may I know not whether there may be many things done in nature in which this may not be said to have a finger this I have in some other passages of the street is further inquired into and shown that as well light as heat may be caused by corrosion which is applicable to congruity and consequently all the rest will be but subsequence in the meantime I would not willingly be guilty of that error which the thrice noble and learned verulam justly takes notice of as such and calls philosophie genus empiricum codin paucorum experimentorum angustius et obscuritate fundatum est for I neither conclude from one single experiment nor are the experiments I make use of all made up on one subject nor rest I any experiment to make it quadrare with any preconceived notion but on the contrary I endeavor to be conversant in diverse kinds of experiments and all and every one of those trials I make the standards or touchstones by which I try all my former notions whether they hold out in weight and measure and touch and etc. for as that body is no other than a counterfeit gold which wants anyone of the properties of gold such as are the malleableness weight color fixedness in the fire indissolubleness in aqua forties and the like though it has all the other so will all those notions be found to be false and deceitful that will not undergo all the trials and tests made of them by experiments and therefore such as will not come up to the desired apex of perfection I rather wholly reject and take new then by piecing and patching endeavor to retain the old as knowing such things at best to be but lame and imperfect and this course I learned from nature whom we find neglectful of the old body and suffering is the case and infirmities to remain without repair and altogether solicitous and careful of perpetuating the species by new individuals and it is certainly the most likely way to erect a glorious structure and temple to nature such as she will be found by any zealous rotary to reside in to begin to build a new upon a sure foundation of experiments but to digress no further from the consideration of the phenomena more immediately explicable by this experiment we shall proceed to show that as to the rising of water in a filter the reason of it will be manifest to him that does take notice that a filter is constituted of a great number of small long solid bodies which lies so close together that the air in its getting in between them does lose of its pressure that it has against the fluid without them by which means the water or liquor not finding so stronger resistance between them as is able to counterbalance the pressure on its superfaces without is raised upward till it meet with the pressure of the air which is able to hinder it and as to the rising of oil melted tallow spirit of wine and cetera in the week of candle or lamp it is evident that it differs in nothing from the former save only in this that in a filter the liquor descends and runs away by another part and in the week the liquor is dispersed and carried away by the flame something there is ascribable to the heat for that it may rarify the more volatile and spiritual parts of those combustible liquors and so being made lighter than the air it may be protruded upwards by that more ponderous fluid body in the form of vapors but this can be ascribed to the ascension of but a very little and most likely of that only which ascends without a week as for the rising of it in a sponge, bread, cotton, etc above the superfaces of the subjacent liquor what has been said about the filter if considered will easily suggest a reason considering that all these bodies abound with small holes or pores from this same principle also this avi the unequal pressure of the air against the unequal surfaces of the water precedes the cause of the accession or incursion of any floating body against the sides of the containing vessel or the uprope incubation of two floating bodies as bubbles, quarks, sticks, straws, etc one towards another as for instance take a glass jar such as AB in the seventh figure and filling it pretty near to the top with water throw into it a small round piece of cork as sea and plunge it all over in water that it be wet so as that the water may rise up by the sides of it then placing it anywhere upon the superfaces about an inch or one inch and a quarter from any side and you shall perceive it by degrees to make perpendicularly toward the nearest part of the side and the nearer it approaches the faster to be moved the reason of which phenomena will be found no other than this that the air has a greater pressure against the middle of the superfaces than it has against those parts that approach nearer and are contiguous to the sides now that the pressure is greater may as I should before in the explication of the third figure be evinced from the flattening of the water in the middle which arises from the gravity of the under fluid for since as I should before if there were no gravity in the under fluid or that it were equal to that of the upper the terminating surface would be spherical and since it is the additional pressure of the gravity of water that makes it so flat it follows that the pressure upon the middle must be greater than towards the sides hence the ball having a stronger pressure against that side of it which respects the middle of superfaces then against that which respects the approximate side must necessarily move towards that part from whence it finds least resistance and so be accelerated as the resistance decrease hence the more the water is raised under that part of its way it is passing above the middle the faster it is moved and therefore you will find it to move faster in E than D and in D than C neither could I find the floating substance to be moved at all until it were placed upon some part of the superfaces that was sensibly elevated above the height of the middle part now that this may be the true cause you may try with a blown bladder and an exactly round ball upon a very smooth side of some pliable body as horn or quicksilver for if the ball be placed under a part of the bladder which is upon one side of the middle of its pressure and you press strongly against bladder you shall find the ball moved from the middle towards the sides having therefore shown the reason of the motion of any float towards the sides the reason of the incursion of any two floating bodies will easily appear for the rising of the water against the sides of either of them is an argument sufficient to show the pressure of the air to be there less than it is further from it where it is not so much elevated and therefore the reason of the motion of the other toward it will be the same as towards the side of the glass only here from the same reason they are mutually moved towards each other whereas the other side of the glass in the former remains fixed if also you gently feel the jar so full with water that the water is protuberant above the sides the same piece of quark that before did hasten towards the sides does now fly from it as fast towards the middle of these surfaces the reason of which will be found no other than this that the pressure of the air is stronger against the sides of the surfaces G and H than against the middle I for sense as I showed before the principle of congruity would make the terminating surface spherical and that the flattening of the surface in the middle is from the abatement of the waters pressure outwards by its country endeavor of its gravity it follows that the pressure in the middle must be less than on the sides and therefore the consequent will be the same as in the former it is very odd to one that considers not the reason of it to see two floating bodies of wood to approach each other as though they were in dude with some magnetical vigor which brings into my mind what I formerly tried with a piece of quark or such like body which I so ordered that by putting a little stick into the same water one part of the said quark would approach and make towards the stick whereas another would deseed and fly away may it would have a kind of verticity so as that if the equator as I may so speak of the quark were placed towards the stick if let alone it would instantly turn its appropriate pole toward it and then run a tilt at it and this was done only by taking a dry quark and wetting one side of it with one small stroke for by this means gently putting it up on the water it would depress the surfaces on every side of it that was dry and therefore the greatest pressure of the air being near those sides caused it either to chase away or else to fly off from any other floating body whereas that side only against which the water ascended was thereby able to attract it remains only that I should determine how high the water or the liquor may by this means be raised in a smaller pipe above the surfaces of that without it and at what height it may be sustained but to determine this it will be exceeding difficult unless I could certainly know how much of the air's pressure is taken off by the smallness of such and such a pipe and whether it may be wholly taken off that is whether there can be a hole or pore so small into which air could not at all enter the water might with its whole force for where there such it is manifest that the water might rise in it to some five or six and thirty English foot high I know not whether the capillary pipes in the bodies of small trees which we call their microscopical pores may not be such and whether the congruity of the sides of the pore may not yet draw the juice even higher than the air was able by its bare pressure to raise it for congruity is a principle that not only unites and holds a body joined to it but which is more attracts and draws a body that is very near it and holds it above its usual height and this is obvious even in a drop of water suspended under any similar or congruent body for besides the ambient pressure that helps to keep it sustained there is the congruity of the bodies that are contiguous this is yet more evident in tenacious and glutinous bodies such as gammas, liquors, syrups, pitch and rosin melted and etc tar, terpentine, balsam, bird lime and etc for there it is evident that the parts of the tenacious body as I may so call it do stick and adhere so closely together that though drawn out into long and very slender cylinders yet they will not easily relinquish one another and this though the bodies be eloquence fluid and in motion by one another which to such as consider a fluid body only as its parts are in a confused irregular motion without taking in also the congruity of the parts one among another and incongruity to some other bodies does appear not a little strange so that besides the incongruity of the ambient fluid to it we are to consider also the congruity of the parts of the contained fluid one with another and this congruity that I may hear a little further explain it is both a tenacious and an attractive power for the congruity in the vibrative motions may be the cause of all kind of attraction not only electrical but magnetical also and therefore it may be also of tenacity and glutinousness for from a perfect congruity of the motions of two distant bodies the intermediate fluid particles are separated and driven away from between them and thereby those congruous bodies are by the encompassing mediums compelled and forced nearer together where for that attractiveness must needs be stronger when by an immediate contact they are forced to be exactly the same as I show more at large in my theory of the magnet and this hints to me the reason of suspension of the mercury many inches name any feet above the usual station of 30 inches for the parts of quicksilver being so very similar and congruous to each other if once united will not easily suffer a diversion and the parts of water that were anyways heterogeneous being by exhalation or rarefaction exhosted the remaining parts being also very similar will not easily part neither and the parts of glass being solid are more difficult to disjoint and water being somewhat similar to both is as it were a medium to unite both the glass and the mercury together so that all three being united and not very dissimilar by means of this contact if care be taken that the tube in erecting be not shocked the quicksilver will remain suspended not withstanding its contrary endeavor of gravity a great height above its ordinary station but if this immediate contact be removed either by a mere separation of them one from another by the force of a shock whereby the other becomes embodied between them and leaks up from the surface some agile parts and so hurling them makes them air or else by some small heterogeneous agile part of the water or air or quicksilver which appears like a bubble and by its jumbling to and fro there is made way for the heterogeneous ether to obtrude itself between the glass and either of the fluids the gravity of mercury precipitated downward with very great violence and if the vessel that holds the restagnating mercury be convenient the mercury will for a time vibrate to and fro with very large reciprocations and at last will remain kept up by the pressure of the external air at the height of near 30 inches and whereas it may be objected that it cannot be that the mere embodying of the ether between these bodies can be the cause since the ether having a free passage always both through the pores of the glass and through those of the fluids there is no reason why it should not make a separation at all times whilst it remains suspended as when it is violently disjoined by a shock to this I answer that though the ether passes between the particles that is through the pores of the bodies so as that any custom or separation being made it has infinite passages to admit its entry into it yet such is the tenacity or attractive virtue of congruity that till it be overcome by the mere strength of gravity or by a shock assisting that conatus of gravity or by an agile particle that is like a lever agitated by the ether and thereby the parts of the congruous substances are separated so far asunder that the strength of congruity is so far weakened as not to be able to reunite them the parts to be taken hold of being removed out of the attractive sphere as I may so speak of the congruity such I say is the tenacity of congruity that it retains and holds the almost contiguous particles of the fluid and suffers them not to be separated till by mere force that attractive or retentive faculty be overcome but the separation being once made beyond the sphere of the attractive activity of congruity that virtue becomes of no effect at all but the mercury freely falls downwards till it meet with the resistance from the pressure of the ambient air able to resist its gravity and keep it forced up in the pipe to the height of about 30 inches thus have I gently raised a steel pendulum by a lodestone to a great angle till by the shaking of my hand I have chance to make a separation between them which is no sooner made but as if the lodestone had retained no attractive virtue the pendulum moves freely from it towards the other side so vast a difference is there between the attractive virtue of the magnet when it acts upon a contiguous and upon a disjoint body and much more must there be between the attractive virtues of congruity upon a contiguous and disjoint body and in truth the attractive virtue is so little upon a body disjoint that though I have with a microscope observed very diligently whether there were any extraordinary protuberance on the side of a drop of water that was exceeding near the end of a green stick but did not touch it I could not perceive the least though I found that as soon as ever it touched it the whole drop would presently unite itself with it so that it seems an absolute contact is requisite to the exercising of the tenacious faculty of congruity end of section 10 observation 6 part 2 recording by Mike Botez