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 Ebullition of the Water out of Springs and Fountains which lie much higher from the Center of the Earth then the Superficies of the Sea from whence it seems to be derived may not be explicated by the rising of Water in a 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 examining this way and finding in it several difficulties almost irremovable I thought upon 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 chusing two heterogeneous fluids such as Water and Oyl I poured in as much Water as filled up the Pipes as high as AB then putting in some Oyl into the Tube AC I deprest the superficies A of the Water to E and BI raised to G which was not so high perpendicularly as the superficies of the Oyl F by the space FI wherefore the proportion of the gravity of these two Liquors was as GH to FE 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 two though they are nothing heterogeneous yet before they would perfectly mix one with another I made trial of the Experiment Nay letting the Tube wherein I tried the Experiment remain for many dayes I observed them not to mix but the superficies of the fresh was rather more then less elevated above that of the Salt Now the proportion of the gravity of Sea-water to that of River-water according to Stevinus and Varenius and as I have since found pretty true by making trial my self is as 46. to 45. that is 46. Ounces of the salt Water will take up no more room then 45. of the fresh Or reciprocally 45 pints of salt-salt-water weigh as much as 46 of fresh But I found the proportion of Brine to fresh Water to be near 13 to 12 Supposing therefore GHM to represent the Sea and FI the height of the Mountain above the Superficies of the Sea FM a Cavern in the Earth beginning at the bottom of the Sea and terminated at the top of the Mountain LM 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 GM to FM be as 45 to 46 then may the Cylinder of salt-Salt-water GM make the Cylinder of Fresh-water 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 Superficies to be no more perpendicularly measured then the height of the Mountains above it 'T 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 the separation of the fresh water from the salt as perhaps some parts of the Earth through which it is to pass may contain a Salt that mixing and uniting with the Sea-salt may precipitate it much after the same manner as the Alkalizate 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 then the same cold insomuch 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 it self between those parts protruded so violently together or else squeeze it upwards into the superiour parts of the Sea where it may more easily obtain room for it self 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 Geograhical 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 comes to pass that there are sometimes salt Springs much higher then the Superficies of the Water And Secondly Why Springs do not run faster and slower according to the varying height made of the Cylinder of sea-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 Superficies 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 supplyed by divers 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 supply'd 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 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 aemulus qui statis temporibus suas evomit resorbet Aquas Which at certain times riseth and falleth after the manner of the Sea A Second in Caermardenshire near Caermarden at a place called Cantred Bichan Qui ut scribit Giraldus naturali die â—is undis deficiens toties exuberans marinos imitatur instabilitates That twice in four and twenty hours
the water can very little or not at all penetrate this therefore retaining always very neer the same dimensions and the other stretching and shrinking according as there is more or less moisture or water in its pores by reason of the make and shape of the parts the whole body must necessarily unwreath and wreath it self And upon this Principle it is very easie to make several sorts of contrivances that should thus wreath and unwreath themselves either by heat and cold or by driness and moisture or by any greater or less force from whatever cause it proceed whether from gravity or weight or from wind which is motion of the Air or from some springing body or the like This had I time I should enlarge much more upon for it seems to me to be the very first footstep of Sensation and Animate motion the most plain simple and obvious contrivance that Nature has made use of to produce a motion next to that of Rarefaction and Condensation by heat and cold And were this Principle very well examin'd I am very apt to think it would afford us a very great help to find out the Mechanism of the Muscles which indeed as farr as I have hitherto been able to examine seems to me not so very perplex as one might imagine especially upon the examination which I made of the Muscles of Crabs Lobsters and several sorts of large Shell-fish and comparing my Observations on them with the circumstances I observ'd in the muscles of terrestrial Animals Now as in this Instance of the Beard of a wilde Oat we see there is nothing else requisite to make it wreath and unwreath it self and to streighten and bend its knee then onely a little breath of moist or dry Air or a small atome almost of water or liquor and a little heat to make it again evaporate for by holding this Beard plac'd and fix'd as I before directed neer a Fire and dipping the tip of a small shred of Paper in well rectify'd spirit of Wine and then touching the wreath'd Cylindrical part you may perceive it to untwist it self and presently again upon the avolation of the spirit by the great heat it will re-twist it self and thus will it move forward and backwards as oft as you repeat the touching it with the spirit of Wine so may perhaps the shrinking and relaxing of the muscles be by the influx and evaporation of some kind of liquor or juice But of this Enquiry I shall add more elsewhere Observ. XXVIII Of the Seeds of Venus looking-glass or Corn Violet FRom the Leaves and Downs and Beards of Plants we come at last to the Seeds and here indeed seems to be the Cabinet of Nature wherein are laid up its Jewels The providence of Nature about Vegetables is in no part manifested more then in the various contrivances about the seed nor indeed is there in any part of the Vegetable so curious carvings and beautifull adornments as about the seed this in the larger sorts of seeds is most evident to the eye nor is it less manifest through the Microscope in those seeds whose shape and structure by reason of their smalness the eye is hardly able to distinguish Of these there are multitudes many of which I have observ'd through a Microscope and find that they do for the most part every one afford exceeding pleasant and beautifull objects For besides those that have various kinds of carv'd surfaces there are other that have smooth and perfectly polish'd surfaces others a downy hairy surface some are cover'd onely with a skin others with a kind of shell others with both as is observable also in greater seeds Schem XVII Schem XVIII This though it appear'd one of the most promising seeds for beauty to the naked eye yet through the Microscope it appear'd but a rude mishapen seed which I therefore drew that I might thereby manifest how unable we are by the naked eye to judge of beauteous or less curious microscopical Objects cutting some of them in sunder I observ'd them to be fill'd with a greenish yellow pulp and to have a very thick husk in proportion to the pulp Observ. XXIX Of the seeds of Tyme THese pretty fruits here represented in the 18. Scheme are nothing else but nine several seeds of Tyme they are all of them in differing posture both as to the eye and the light nor are they all of them exactly of the same shape there being a great variety both in the bulk and figure of each seed but they all agreed in this that being look'd on with a Microscope they each of them exactly resembled a Lemmon or Orange dry'd and this both in shape and colour Some of them are a little rounder of the shape of an Orange as A and B they have each of them a very conspicuous part by which they were join'd to their little stalk and one of them had a little piece of stalk remaining on the opposite side of the seed you may perceive very plainly by the Figure is very copped and prominent as is very usual in Lemmons which prominencies are express'd in D E and F. They seem'd each of them a little creas'd or wrinckled but E was very conspicuously furrow'd as if the inward make of this seed had been somewhat like that of a Lemmon also but upon dividing several seeds with a very sharp Pen-knife and examining them afterward I found their make to be in nothing but bulk differing from that of Peas that is to have a pretty thick coat and all the rest an indifferent white pulp which seem'd very close so that it seems Nature does not very much alter her method in the manner of inclosing and preserving the vital Principle in the seed in these very small grains from that of Beans Peas c. The Grain affords a very pretty Object for the Microscope namely a Dish of Lemmons plac'd in a very little room should a Lemmon or Nut be proportionably magnify'd to what this seed of Tyme is it would make it appear as bigg as a large Hay-teek and it would be no great wonder to see Homers Iliads and Homer and all cramm'd into such a Nut-shell We may perceive even in these small Grains as well as in greater how curious and carefull Nature is in preserving the seminal principle of Vegetable bodies in what delicate strong and most convenient Cabinets she lays them and closes them in a pulp for their safer protection from outward dangers and for the supply of convenient alimental juice when the heat of the Sun begins to animate and move these little automanâ—â—s or Engines as if she would from the ornaments wherewith she as deckt these Cabinets hint to us that in them she has laid up her Jewels and Master-pieces And this if we are but diligent in observing we shall find her method throughout There is no curiosity in the Elemental kingdom if I may so call the bodies of Air Water Earth that are comparable in
called by the Names of Driness and Moisture though these two names are not comprehensive enough being commonly used to signifie 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 then others and that water let fall upon a Feather the whiter side of a Colworâ— and some other leaves or upon almost any dusty unctuous or resinous superficies will not at all adhere to them but easily tumble off from them like a solid Bowl whereas if dropt upon Linnen Paper Clay green Wood c. it will not be taken off without leaving some part of it behind 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 metalline bodies And that we may the better finde 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 a body as I have elsewhere made probabable the parts of a body are thereby made so loose from one another that they easily move any way 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 vibrating motion as on a Milstone turn'd 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 the Drumsticks By this means the sand in the dish which before lay like a dull and unactive body becomes a perfect fluid and ye can no sooner make a hole in it with your finger but it is immediately filled up again and the upper surface of it levell'd Nor can you bury a light body as a piece of Cork under it but it presently emerges or swims as 't were on the 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 't were 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 dos imitate and all this meerly caused by the vehement agitation of the conteining 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 sustain'd by some other on either side Nor will it suffer any Body to be beneath it unless it be a heavier then it self 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 be screw'd so firm and hard that though it has a convenient head to it yet it can by no means be unscrew'd by the fingers if I say you attempt to unscrew this whilst grated on by the file it will be found to undoe and turn very easily The first of these Examples manifests how a body actually divided into small parts becomes a fluid And the latter manifest by what means the agitation of heat so easily loosens and unties the parts of solid and firm bodies Nor need we suppose heat to be any thing else besides such a 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 I there shew 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 unapt 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 Aether 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 tincture or solution of terrestrial and aqueous particles dissolv'd into it and agitated by it just as the tincture of Cocheneel is nothing but some finer dissoluble parts of that Concrete lick'd up or dissolv'd 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 Rarefaction and Condensation For as in tinctures one grain of some strongly tinging substance may sensibly colour some hundred thousand grains of appropriated Liquors so as every drop of it has its proportionate share and be sensibly ting'd as I have try'd both with Logwood and Cocheneel And as some few grains of Salt is able to infect as great a quantity as may be found by praecipitations though not so easily by the sight or aste so the Air which seems to be but as 't were a tincture or saline substance dissolv'd and agitated by the fluid and agil Aether may disperse and expand it self into a vast space if it have 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 colour 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 sufficed in a rarify'd state to fill some hundred thousand spaces of Aether be compris'd 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 filtre without praecipitation as we are able to separate the Air from the Aether by Glass and several other bodies And though we are yet unable and ignorant of the ways of praecipitating Air out of the Aether as we can Tinctures and Salts out of several dissolvents yet neither of these seeming impossible from the nature of the things nor so improbable
ebbing and flowing resembleth the unstable motions of the Sea The Phaenomena 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 unto Newton of which Camden relates himself to be certified by a Letter from a Learned Friend of his that observed it Fons abest hinc c. 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 't 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 a Sea very remote from those parts and where the Tides are much differing from those of the approximate shores A Fourth lies in Westmorland near the River Loder Qui instar Euripi saepius in die reciprocantibus undis fluit refluit which ebbs and flows many times a day This may proceed from its being supplyed from many Channels coming from several parts of the Sea lying sufficiently distant asunder to have the times of High-water differing enough one from the other so as that whensoever 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 Menstruums Unctuous Gums in Oyls the mixing of Wine and Water c. 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 co-efficient in the most considerable Operations of Nature As in those of Heat and Light and consequently of Rarefaction and Condensation Hardness and Fluidness Perspicuity and Opacousness Refractions and Colours c. Nay 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 this Treatise further enquired into and shewn that as well Light as Heat may be caused by corrosion which is applicable to congruity and consequently all the rest will be but subsequents In the mean time I would not willingly be guilty of that Error which the thrice Noble and Learned Verulam justly takes notice of as such and calls Philosophiae Genus Empiricum quod in paucorum Experimentorum Angustiis Obscuritate fundatum est For I neither conclude from one single Experiment nor are the Experiments I make use of all made upon one Subject Nor wrest I any Experiment to make it quadrare with any preconceiv'd Notion But on the contrary 〈◊〉 endeavour to be conversant in divers kinds of Experiments and all 〈◊〉 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 c. For as that Body is no other then a Counterfeit Gold which wants any one of the Proprieties of Gold such as are the Malleableness Weight Colour Fixtness in the Fire Indissolubleness in Aqua fortis 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 endeavour 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 its Decaies and Infirmities to remain without repair and altogether sollicitous 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 Votary to refide in to begin to build a new upon a sure Foundation of Experiments But to digress no further from the consideration of the Phaenomena more immediately explicable by this Experiment we shall proceed to shew That as to the rising of Water in a Filtre the reason of it will be manifest to him that does take notice that a Filtre is constituted of a great number of small long solid bodies which lie so close together that the Air in its getting in between them doth lose of its pressure that it has against the Fluid without them by which means the Water or Liquor not finding so strong a resistance between them as is able to counter-ballance the pressure on its superficies without is raised upward till it meet with a pressure of the Air which is able to hinder it And as to the Rising of Oyl melted Tallow Spirit of Wine c. in the Week of a Candle or Lamp it is evident that it differs in nothing from the former save only in this that in a Filtre 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 ratifie the more volatil and spirituous parts of those combustible Liquors and so being made lighter then the Air it may be protruded upwards by that more ponderous fluid body in the Form of Vapours but this can be ascribed to the ascension of but a very little and most likely of that only which ascends without the Week As for the Rising of it in a Spunge Bread Cotton c. above the superficies of the subjacent Liquor what has been said about the Filtre if considered will easily suggest a reason considering that all these bodies abound with small holes or pores From this same Principle also viz. the unequal pressure of the Air against the unequal superficies of the water proceeds the cause of the accession or incursion of any floating body against the sides of the containing Vessel or the appropinquation of two floating bodies as Bubbles Corks Sticks Straws c. one towards another As for instance Take a Glass-jar such as AB in the seventh Figure and filling it pretty near the top with water throw into it a small round piece of Cork as C 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 any where upon the superficies about an inch or one inch and a
fluid to it we are to consider also the congruity of the parts of the contein'd fluid one with another And this Congruity that I may here a little further explain it is both a Tenaceous 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 droven away from between them and thereby those congruous bodies are by the incompassing mediums compell'd and forced neerer together wherefore that attractiveness must needs be stronger when by an immediate contact they are forc'd to be exactly the same As I shew more at large in my Theory of the Magnet And this hints to me the reason of the suspension of the Mercury many inches nay many feet above the usual station of 30 inches For the parts of Quick-silver being so very similar and congruous to each other if once united will not easily suffer a divulsion And the parts of water that were any wayes heterogeneous being by exantlation or rarefaction exhausted the remaining parts being also very similar will not easily part neither And the parts of the Glass being solid are more difficulty disjoyn'd and the 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 shogged the Quicksilver will remain suspended notwithstanding its contrary indeavour of Gravity a great height above its ordinary Station but if this immediate Contact be removed either by a meer separation of them one from another by the force of a shog whereby the other becomes imbodied between them and licks up from the surface some agil parts and so hurling them makes them air or else by some small heterogeneous agil 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 Aether to obtrude it self between the Glass and either of the other Fluids the Gravity of Mercury precipitates it 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 neer thirty inches And whereas it may be objected that it cannot be that the meer imbodying of the Aether between these bodies can be the cause since the Aether having a free passage alwayes 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 dis-joyned by a shog To this I answer That though the Aether passes between the Particles that is through the Pores of bodies so as that any chasme 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 meer strength of Gravity or by a shog assisting that Conatus of Gravity or by an agil Particle that is like a leaver agitated by the Aether 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 meer 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 a 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 thirty inches Thus have I gently raised a Steel pendulum by a Loadstone to a great Angle till by the shaking of my hand I have chanced to make a separation between them which is no sooner made but as if the Loadstone 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 disjoyned body and much more must there be between the attractive virtues of congruity upon a contiguous and disjoyned body and in truth the attractive virtue is so little upon a body disjoyned 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 neer to 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 toucht it the whole drop would presently unite it self with it so that it seems an absolute contact is requisite to the exercising of the tenacious faculty of congruity Observ. VII Of some Phaenomena of Glass drops THese Glass Drops are small â—parcels of coarse green Glass taken out of the Pots that contain the Metal as they call it in fusion upon the end of an Iron Pipe and being exceeding hot and thereby of a kind of sluggish fluid Consistence are suffered to drop from thence into a Bucket of cold Water and in it to lye till they be grown sensibly cold Some of these I broke in the open air by snapping off a little of the small stem with my fingers others by crushing it with a small pair of Plyers which I had no sooner done then the whole bulk of the drop flew violently with a very brisk noise into multitudes of small pieces some of which were as small as dust though in some there were remaining pieces pretty large without any flaw at all and others very much flaw'd which by rubbing between ones fingers was easily reduced to dust these dispersed every way so violently that some of them pierced my skin I could not find either with my naked Eye or a Microscope that any of the broken pieces were of a regular figure nor any one like another but for the most part those that flaw'd off in large pieces were prettily branched The ends of others of these drops I nipt off whilst all the bodies and ends of them lay buried under the water which like the former flew all to pieces with as brisk a noise and as strong a motion Others of these I tried to break by
this place Zeictically to examine and positively to prove what particular kind of motion it is that must be the efficient of Light for though it be a motion yet 't is not every motion that produces it since we find there are many bodies very violently mov'd which yet afford not such an effect and there are other bodies which to our other senses seem not mov'd so much which yet shine This Water and quick-silver and most other liquors heated shine not and several hard bodies as Iron Silver Brass Copper Wood c. though very often struck with a hammer shine not presently though they will all of them grow exceeding hot whereas rotten Wood rotten Fish Sea water Gloworms c. have nothing of tangible heat in them and yet where there is no stronger light to affect the Sensory they shine some of them so Vividly that one may make a shift to read by them It would be too long I say here to insert the discursive progress by which I inquir'd after the proprieties of the motion of Light and therefore I shall only add the result And First I found it ought to be exceeding quick such as those motions of fermentation and putrefaction whereby certainly the parts are exceeding nimbly and violently mov'd and that because we find those motions are able more minutely to shatter and divide the body then the most violent heats or menstruums we yet know And that fire is nothing else but such a dissolution of the Burning body made by the most universal menstruum of all sulphureous bodies namely the Air we shall in an other place of this Tractate endeavour to make probable And that in all extreamly hot shining bodies there is a very quick motion that causes Light as well as a more robust that causes Heat may be argued from the celerity wherewith the bodyes are dissolv'd Next it must be a Vibrative motion And for this the newly mention'd Diamond affords us a good argument since if the motion of the parts did not return the Diamond must after many rubbings decay and be wasted but we have no reason to suspect the latter especially if we consider the exceeding difficulty that is found in cutting or wearing away a Diamond And a Circular motion of the parts is much more improbable since if that were granted and they be suppos'd irregular and Angular parts I see not how the parts of the Diamond should hold so firmly together or remain in the same sensible dimensions which yet they do Next if they be Globular and mov'd only with a turbinated motion I know not any cause that can impress that motion upon the pellucid medium which yet is done Thirdly any other irregular motion of the parts one amongst another must necessarily make the body of a fluid consistence from which it is far enough It must therefore be a Vibrating motion And Thirdly That it is a very short vibrating motion I think the instances drawn from the shining of Diamonds will also make probable For a Diamond being the hardest body we yet know in the World and consequently the least apt to yield or bend must consequently also have its vibrations exceeding short And these I think are the three principal proprieties of a motion requisite to produce the effect call'd Light in the Object The next thing we are to consider is the way or manner of the trajection of this motion through the interpos'd pellucid body to the eye And here it will be easily granted First That it must be a body susceptible and impartible of this motion that will deserve the name of a Transparent And next that the parts of such a body must be Homogeneous or of the same kind Thirdly that the constitution and motion of the parts must be such that the appulse of the luminous body may be communicated or propagated through it to the greatest imaginable distance in the least imaginable time though I see no reason to affirm that it must be in an instant For I know not any one Experiment or observation that does prove it And whereas it may be objected That we see the Sun risen at the very instant when it is above the sensible Horizon and that we see a Star hidden by the body of the Moon at the same instant when the Star the Moon and our Eye are all in the same line and the like Observations or rather suppositions may be urg'd I have this to answer That I can as easily deny as they affirm for I would fain know by what means any one can be assured any more of the Affirmative then I of the Negative If indeed the propagation were very slow 't is possible something might be discovered by Eclypses of the Moon but though we should grant the progress of the light from the Earth to the Moon and from the Moon back to the Earth again to be full two Minutes in performing I know not any possible means to discover it nay there may be some instances perhaps of Horizontal Eclypses that may seem very much to favour this supposition of the slower progression of Light then most imagine And the like may be said of the Eclypses of the Sun c. But of this only by the by Fourthly That the motion is propagated every way through an Homogeneous medium by direct or straight lines extended every way like Rays from the center of a Sphere Fifthly in an Homogeneous medium this motion is propagated every way with equal velocity whence necessarily every pulse or vitration of the luminous body will generate a Sphere which will continually increase and grow bigger just after the same manner though indefinitely swifter as the waves or rings on the surface of the water do swell into bigger and bigger circles about a point of it where by the sinking of a Stone the motion was begun whence it necessarily follows that all the parts of these Spheres undulated through an Homogeneous medium cut the Rays at right angles But because all transparent mediums are not Homogeneous to one another therefore we will next examine how this pulse or motion will be propagated through differingly transparent mediums And here according to the most acute and excellent Philosopher Des Cartes I suppose the sign of the angle of inclination in the first medium to be to the sign of refraction in the second As the density of the first to the density of the second By density I mean not the density in respect of gravity with which the refractions or transparency of mediums hold no proportion but in respect onely to the trajection of the Rays of light in which respect they only differ in this that the one propagates the pulse more easily and weakly the other more slowly but more strongly But as for the pulses themselves they will by the refraction acquire another propriety which we shall now endeavour to explicate We will suppose therefore in the first Figure ACFD to be a physical Ray or ABC and DEF to
to be made up of abundance of small Balls which do but just touch each other and yet there being so many contacts they make a firm hard mass or a Stone much harder then Free-stone Next though we can by a Microscope discern so curious a shape in the particles yet to the naked eye there scarce appears any such thing which may afford us a good argument to think that even in those bodies also whose texture we are not able to discern though help'd with Microscopes there may be yet latent so curious a Schematisme that it may abundantly satisfie the curious searcher who shall be so happy as to find some way to discover it Next we here find a Stone though to the naked eye a very close one yet every way perforated with innumerable pores which are nothing else but the interstitia between those multitudes of minute globular particles that compose the bulk it self and these pores are not only discover'd by the Microscope but by this contrivance I took a pretty large piece of this stone and covering it all over with cement save only at two opposite parts I found my self able by blowing in at one end that was left open to blow my spittle with which I had wet the other end into abundance of bubbles which argued these pores to be open and pervious through the whole stone which affords us a very pretty instance of the porousness of some seemingly close bodies of which kind I shall anon have occasion to subjoyn many more tending to prove the same thing I must not here omit to take notice that in this body there is not a vegetative faculty that should so contrive this structure for any peculiar use of Vegetation or growth whereas in the other instances of vegetable porous bodies there is an anima or forma informans that does contrive all the Structures and Mechanismes of the constituting body to make them subservient and usefull to the great Work or Function they are to perform And so I ghess the pores in Wood and other vegetables in bones and other Animal substances to be as so many channels provided by the Great and Alwise Creator for the conveyance of appropriated juyces to particular parts And therefore that this may tend or be pervious all towards one part and may have impediments as valves or the like to any other but in this body we have very little reason to suspect there should be any such design for it is equally pervious every way not onely forward but backwards and side-ways and seems indeed much rather to be Homogeneous or similar to those pores which we may with great probability believe to be the channels of pellucid bodies not directed or more open any one way then any other being equally pervious every way And according as these pores are more or greater in respect of the interstitial bodies the more transparent are the so constituted concretes and the smaller those pores are the weaker is the Impulse of light communicated through them though the more quick be the progress Upon this Occasion I hope it will not be altogether unseasonable if I propound my conjectures and Hypothesis about the medium and conveyance of light I suppose then that the greatest part of the Interstitia of the world that lies between the bodies of the Sun and Starrs and the Planets and the Earth to be an exceeding fluid body very apt and ready to be mov'd and to communicate the motion of any one part to any other part though never so far distant Nor do I much concern my self to determine what the Figure of the particles of this exceedingly subtile fluid medium must be nor whether it have any interstitiated pores or vacuities it being sufficient to solve all the Phaenomena to suppose it an exceedingly fluid or the most fluid body in the world and as yet impossible to determine the other difficulties That being so exceeding fluid a body it easily gives passage to all other bodies to move to and fro in it That it neither receives from any of its parts or from other bodies nor communicates to any of its parts or to any other body any impulse or motion in a direct line that is not of a determinate quickness And that when the motion is of such determinate swiftness it both receives and communicates or propagates an impulse or motion to any imaginable distance in streight lines with an unimaginable celerity and vigour That all kind of solid bodies consist of pretty massie particles in respect of the particles of this fluid medium which in many places do so touch each other that none of this fluid medium interposes much after the same mannner to use a gross similitude as a heap of great stones compass one great congeries or mass in the midst of the water That all fluid bodies which we may call tangible are nothing but some more subtile parts of those particles that serve to constitute all tangible bodies That the water and such other fluid bodies are nothing but a congeries of particles agitated or made fluid by it in the same manner as the particles of Salt are agitated or made fluid by a parcel of water in which they are dissolv'd and subsiding to the bottom of it constitute a fluid body much more massie and dense and less fluid then the pure water it self That the air on the other side is a certain company of particles of quite another kind that is such as are very much smaller and more easiely moveable by the motion of this fluid medium much like those very subtile parts of Cochenel and other very deep tinging bodies where by a very small parcel of matter is able to tinge and diffuse it self over a very great quantity of the fluid dissolvent or somewhat after that manner as smoak and such like minute bodies or steams are observ'd to tinge a very great quantity of air onely this last similitude is deficient in one propriety and that is a perpetuity or continuance in that state of commixture with the air but the former does more neerly approach to the nature and manner of the air 's being dissolv'd by this fluid or Aether And this Similitude will further hold in these proprieties that as those tinctures may be increased by certain bodies so may they be precipitated by others as I shall afterwards shew it to be very probable that the like accidents happen even to the Air it self Further as these solutions and tinctures do alter the nature of these fluid bodies as to their aptness to propagate a motion or impulse through them even so does the particles of the Air Water and other fluid bodies and of Glass Crystal c. which are commixt with this bulk of the Aether alter the motion of the propagated pulse of light that is where these more bulkie particles are more plentifull and consequently a lesser quantity of the Aether between them to be mov'd there the motion must necessarily
be the swifter though not so robust which will produce those effects which I have I hope with some probability ascribed to it in the digression about Colours at the end of the Observations on Mâ—scovy-glass Now that other Stones and those which have the closest and hardest textures and seem as far as we are able to discover with our eyes though help'd with the best Microscopes freest from pores are yet notwithstanding replenish'd with them an Instance or two will I suppose make more probable A very solid and unflaw'd piece of cleer white Marble iâ— it be well polish'd and glaz'd has so curiously smooth a surface that the best and most polish'd surface of any wrought-glass seems not to the naked eye nor through a Microscope to be more smooth and less porons And yet that this hard close body is replenish'd with abundance of pores I think these following Experiments will sufficiently prove The first is That if you take such a piece and for a pretty while boyl it in Turpentine and Oyl of Turpentine you shall find that the stone will be all imbu'd with it and whereas before it look'd more white but more opacous now it will look more greasie but be much more transparent and if you let it lie but a little while and then break off a part of it you shall find the unctuous body to have penetrated it to such a determinate depth every way within the surface This may be yet easier try'd with a piece of the same Marble a little warm'd in the fire and then a little Pitch or Tarr melted on the top of it for these black bodies by their â—â—sinoating themselves into the invisible pores of the stone ting it with so black a hue that there can be no further doubt of the truth of this assertion that it abounds with small imperceptible pores Now that other bodies will also sink into the pores of Marble besides unctuous I have try'd and found that a very Blue tincture made in spirit of Vrine would very readily and easily sink into it as would also several tinctures drawn with spirit of Wine Nor is Marble the only seemingly close stone which by other kinds of Experiments may be found porous for I have by this kind of Experiment on divers other stones found much the same effect and in some indeed much more notable Other stones I have found so porous that with the Microscope I could perceive several small winding holes much like Worm-holes as I have noted in some kind of Purbeck-stone by looking on the surface of a piece newly flaw'd off for if otherwise the surface has been long expos'd to the Air or has been scraped with any tool those small caverns are fill'd with dust and disappear And to confirm this Conjecture yet further I shall here insert an excellent account given into the Royal Society by that Eminently Learned Physician Doctor Goddard of an Experiment not less instructive then curious and accurate made by himself on a very hard and seemingly close stone call'd Oculus Mundi as I find it preserv'd in the Records of that Honourable Society A small stone of the kind call'd by some Authours Oculus Mundi being dry and cloudy weigh'd 5 209 256 Grains The same put under water for a night and somewhat more became transparent and the superficies being wiped dry weighed 6 3 256 Grains The difference between these two weights 0 50 256 of a Grain The same Stone kept out of water one Day and becoming cloudy again weighed 5 225 256 Graines Which was more then the first weight 0 16 256 of a Grain The same being kept two Days longer weighed 5 20â— 256 Graines Which was less then at first 0 7 256 of a Grain Being kept dry something longer it did not grow sensibly lighter Being put under water for a night and becoming again transparent and wiped dry the weight was 6 3 256 Grains the same with the first after putting in water and more then the last weight after keeping of it dry â— 57 256 of a Grain Another Stone of the same kind being variegated with milky white and gray like some sorts of Agates while it lay under water was alwaies invironed with little Bubbles such as appear in water a little before boyling next the sides of the Vessel There were also some the like Bubbles on the Surface of the water just over it as if either some exhalations came out of it or that it did excite some fermentation in the parts of the water contiguous to it There was little sensible difference in the transparency of this Stone before the putting under water and after To be sure the milky white parts continued as before but more difference in weight then in the former For whereas before the putting into the water the weight was 18 9â— 128 Graines After it had lyen in about four and twenty hours the weight was 20 â—7 128 Graines so the difference was 1 58 128 Graines The same Stone was infused in the water scalding hot and so continued for a while after it was cold but got no more weight then upon infusing in the cold neither was there any sensible Difference in the weight both times In which Experiment there are three Observables that seem very manifestly to prove the porousness of these seemingly close bodies the first is their acquiring a transparency and losing their whiteness after sleeping in water which will seem the more strongly to argue it if what I have already said about the making transparent or clarifying of some bodies as the white powder of beaten Glass and the froth of some glutinous transparent liquor be well consider'd for thereby it will seem rational to think that this transparency arises from the insinuation of the water which has much the same refraction with such stony particles as may be discoverd by Sand view'd with a Microscope into those pores which were formerly repleat with air that has a very differing refraction and consequently is very reflective which seems to be confirm'd by the second Observable namely the increase of weight after steeping and decrease upon drying And thirdly seem'd yet more sensibly confirm'd by the multitude of bubbles in the last Experiment We find also most Acid Salts very readily to dissolve and separate the parts of this body one from another which is yet a further Argument to confirm the porousness of bodies and will serve as such to shew that even Glass also has an abundance of pores in it since there are several liquors that with long staying in a Glass will so Corrode and eat into it as at last to make it perviouâ— to the liquor it contain'd of which I have seen very many Instances Since therefore we find by other proofs that many of those bodies which we think the most solid ones and appear so to our sight have notwithstanding abundance of those grosser kind of pores which will admit several kinds of liquors into them why
form to those of Minerals Air and Water having no form at all unless a potentiality to be form'd into Globules and the clods and parcels of Earth are all irregular whereas in Minerals she does begin to Geometrize and practise as 't were the first principles of Mechanicks shaping them of plain regular figures as triangles squares c. and tetraedrons cubes c. But none of their forms are comparable to the more compounded ones of Vegetables For here she goes a step further forming them both of more complicated shapes and adding also multitudes of curious Mechanick contrivances in their structure for whereas in Vegetables there was no determinate number of the leaves or branches nor no exactly certain figure of leaves or flowers or seeds in Animals all those things are exactly defin'd and determin'd and where-ever there is either an excess or defect of those determinate parts or limbs there has been some impediment that has spoil'd the principle which was most regular Here we shall find not onely most curiously compounded shapes but most stupendious Mechanisms and contrivances here the ornaments are in the highest perfection nothing in all the Vegetable kingdom that is comparable to the deckings of a Peacock nay to the curiosity of any feather as I elsewhere shew nor to that of the smallest and most despicable Fly But I must not stay on these speculations though perhaps it were very well worth while for one that had leisure to see what Information may be learn'd of the nature or use or virtues of bodies by their several forms and various excellencies and properties Who knows but Adam might from some such contemplation give names to all creatures If at least his names had any significancy in them of the creature's nature on which he impos'd it as many upon what grounds I know not have suppos'd And who knows but the Creator may in those characters have written and engraven many of his most mysterious designs and counsels and given man a capacity which assisted with diligence and industry may be able to read and understand them But not to multiply my digression more then I can the time I will proceed to the next which is Observ. XXX Of the Seeds of Poppy THe small seeds of Poppy which are described in the 19. Scheme both for their smalness multiplicity and prettiness as also for their admirable soporifick quality deserve to be taken notice of among the Schem XIX Schem XX. other microscopical seeds of Vegetables For first though they grow in a Case or Hive oftentimes bigger then one of these Pictures of the microscopical appearance yet are they for the most part so very little that they exceed not the bulk of a small Nitt being not above â— 32 part of an Inch in Diameter whereas the Diameter of the Hive of them oftentimes exceeds two Inches so that it is capable of containing neer two hundred thousand and so in all likelihood does contain a vast quantity though perhaps not that number Next for their prettiness they may be compar'd to any microscopical seed I have yet seen for they are of a dark brownish red colour curiously Honey comb'd all over with a very pretty variety of Net-work or a small kind of imbosment of very orderly rais'd ridges the surface of them looking not unlike the inside of a Beev's stomack But that which makes it most considerable of all is the medicinal virtues of it which are such as are not afforded us by any Mineral preparation and that is for the procuring of sleep a thing as necessary to the well-being of a creature as his meat and that which refreshes both the voluntary and rational faculties which whil'st this affection has seis'd the body are for the most part unmov'd and at rest And methinks Nature does seem to hint some very notable virtue or excellency in this Plant from the curiosity it has bestow'd upon it First in its flower it is of the highest scarlet-Dye which is indeed the prime and chiefest colour and has been in all Ages of the world most highly esteem'd Next it has as much curiosity shew'd also in the husk or case of the seed as any one Plant I have yet met withall and thirdly the very seeds themselves the Microscope discovers to be very curiously shap'd bodies and lastly Nature has taken such abundant care for the propagation of it that one single seed grown into a Plant is capable of bringing some hundred thousands of seeds It were very worthy some able man's enquiry whether the intention of Nature as to the secundary end of Animal and Vegetable substances might not be found out by some such characters and notable impressions as these or from divers other circumstances as the figure colour place time of flourishing springing and fading duration taste smell c. For if such there are as an able Physician upon good grounds has given me cause to believe we might then insteed of studying Herbals where so little is deliver'd of the virtues of a Plant and less of truth have recourse to the Book of Nature it self and there find the most natural usefull and most effectual and specifick Medicines of which we have amongst Vegetables two very noble Instances to incourage such a hope the one of the Iesuite powder for the cure of intermitting Feaâ—â—â—s and the other of the juice of Poppy for the curing the defect of sleeping Observ. XXXI Of Purslane-seed THe Seeds of Purslane seem of very notable shapes appearing through the Microscope shap'd somewhat like a nautilus or Porcelane shell as may be seen in the XX. Scheme it being a small body coyl'd round in the manner of a Spiral at the greater end whereof which represents the mouth or orifice of the Shell there is left a little white transparent substance like a skin represented by BBBB which seems to have been the place whereunto the stem was join'd The whole surface of this Coclea or Shell is cover'd over with abundance of little prominencies or buttons very orderly rang'd into Spiral rows the shape of each of which seem'd much to resemble a Wart upon a mans hand The order variety and curiosity in the shape of this little seed makes it a very pleasant object for the Microscope one of them being cut asunder with a very sharp Pen-knife discover'd this carved Casket to be of a brownish red and somewhat transparent substance and manifested the inside to be fill'd with a whitish green substance or pulp the Bed wherein the seminal principle lies invelop'd There are multitudes of other seeds which in shape represent or imitate the forms of divers other sorts of Shells as the seed of Scurvy-grass very much resembles the make of a Concha Venerea a kind of Purcelane Shell others represent several sorts of larger fruits sweat Marjerome and Pot-marjerome represent Olives Carret seeds are like a cleft of a Coco-Nut Husk others are like Artificial things as Succory seeds are like a Quiver full
the highest Wisdom and Providence Upon the Anatomy or Dissection of the Head I observ'd these particulars First that this outward skin like the Cornea of the eyes of the greater Animals was both flexible and transparent and seem'd through the Microscope perfectly to resemble the very substance of the Cornea of a man's eye for having cut out the cluster and remov'd the dark and mucous stuff that is subjacent to it I could see it transparent like a thin piece of skin having as many cavities in the inside of it and rang'd in the same order as it had protuberances on the outside and this propriety I found the same in all the Animals that had it whether Flies or Shell-Fish Secondly I found that all Animals that I have observ'd with those kind of eyes have within this Cornea a certain cleer liquor or juice though in a very little quantity and I observ'd thirdly that within that cleer liquor they had a kind of dark mucous lining which was all spread round within the cavity of the cluster and seem'd very neer adjoining to it the colour of which in some Flies was grey in others black in others red in others of a mix'd colour in others spotted and that the whole clusters when look'd on whil'st the Animal was living or but newly kill'd appear'd of the same colour that this coat as I may so call it appear'd of when that outward skin or Cornea was remov'd Fourthly that the rest of the capacity of the clusters was in some as in Dragon Flies c. hollow or empty in others fill'd with some kind of substance in blue Flies with a reddish musculous substance with fibres tending from the center or bottom outwards and divers other with various and differing kinds of substances That this curious contrivance is the organ of sight to all those various Crustaceous Animals which are furnish'd with it I think we need not doubt if we consider but the several congruities it has with the eyes of greater creatures As first that it is furnish'd with a Cornea with a transparent humour and with a uvea or retina that the Figure of each of the small Hemispheres are very Spherical exactly polish'd and most vivid lively and plump when the Animal is living as in greater Animals and in like manner dull flaccid and irregular or shrunk when the Animal is dead Next that those creatures that are furnish'd with it have no other organs that have any resemblance to the known eyes of other creatures Thirdly that those which they call the eyes of Crabs Lobsters Shrimps and the like and are really so are Hemispher'd almost in the same manner as these of Flies are And that they really are so I have very often try'd by cutting off these little movable knobs and putting the creature again into the water that it would swim to and fro and move up and down as well as before but would often hit it self against the rocks or stones and though I put my hand just before its head it would not at all start or fly back till I touch'd it whereas whil'st those were remaining it would start back and avoid my hand or a stick at a good distance before it touch'd it And if in crustaceous Sea-animals then it seems very probable also that these knobs are the eyes in crustaceous Insects which are also of the same kind onely in a higher and more active Element this the conformity or congruity of many other parts common to either of them will strongly argue their crustaceous armour their number of leggs which are six beside the two great claws which answer to the wings in Insects and in all kind of Spiders as also in many other Insects that want wings we shall find the compleat number of them and not onely the number but the very shape figure joints and claws of Lobsters and Crabs as is evident in Scorpions and Spiders as is visible in the second Figure of the 31. Scheme and in the little Mite-worm which I call a Land-crab describ'd in the second Figure of the 33. Scheme but in their manner of generation being oviparous c. And it were very worthy observation whether there be not some kinds of transformation and metamorphosis in the several states of crustaceous water-animals as there is in several sorts of Insects for if such could be met with the progress of the variations would be much more conspicuous in those larger Animals then they can be in any kind of Insects our colder Climate affords These being their eyes it affords us a very pretty Speculation to contemplate their manner of vision which as it is very differing from that of biocular Animals so is it not less admirable That each of these Pearls or Hemispheres is a perfect eye I think we need not doubt if we consider onely the outside or figure of any one of them for they being each of them cover'd with a transparent protuberant Cornea and containing a liquor within them resembling the watry or glassie humours of the eye must necessarily refract all the parallel Rays that fall on them out of the air into a point not farr distant within them where in all probability the Retina of the eye is placed and that opacous dark and mucous inward coat that I formerly shew'd I found to subtend the concave part of the cluster is very likely to be that tunicle or coat it appearing through the Microscope to be plac'd a little more than a Diameter of those Pearls below or within the tunica cornea And if so then is there in all probability a little Picture or Image of the objects without painted or made at the bottom of the Retina against every one of those Pearls so that there are as many impressions on the Retina or opacous skin as there are Pearls or Hemispheres on the cluster But because it is impossible for any protuberant surface whatsoever whether sphaerial or other so to refract the Rays that come from farr remote lateral points of any Object as to collect them again and unite them each in a distinct point and that onely those Rays which come from some point that lies in the Axis of the Figure produc'd are so accurately refracted to one and the same point again and that the lateral Rays the further they are remov'd the more imperfect is their refracted confluence It follows therefore that onely the Picture of those parts of the external objects that lie in or neer the Axis of each Hemisphere are discernably painted or made on the Retina of each Hemisphere and that therefore each of them can distinctly sensate or see onely those parts which are very neer perpendicularly oppos'd to it or lie in or neer its optick Axis Now though there may be by each of these eye-pearls a representation to the Animal of a whole Hemisphere in the same manner as in a man's eye there is a picture or sensation in the Retina of all the objects
Animal surviv'd several motions in the head thorax and belly very distinctly of differing kinds which I may perhaps elsewhere endeavour more accurately to examine and to shew of how great benefit the use of a Microscope may be for the discovery of Nature's course in the operations perform'd in Animal bodies by which we have the opportunity of observing her through these delicate and pellucid teguments of the bodies of Insects acting according to her usual course and way undisturbed whereas when we endeavour to pry into her secrets by breaking open the doors upon her and dissecting and mangling creatures whil'st there is life yet within them we find her indeed at work but put into such disorder by the violence offer'd as it may easily be imagin'd how differing a thing we should find if we could as we can with a Microscope in these smaller creatures quietly peep in at the windows without frighting her out of her usual byas The form of the whole creature as it appear'd in the Microscope may without troubling you with more descriptions be plainly enough perceiv'd by the Scheme the hinder part or belly consisting of eight several jointed parts namely ABCDEFGH of the first Figure from the midst of each of which on either side issued out three or four small brisles or hairs I I I I I the tail was divided into two parts of very differing make one of them namely K having many tufts of hair or brisles which seem'd to serve both for the finns and tail for the Oars and Ruder of this little creature wherewith it was able by frisking and bending its body nimbly to and fro to move himself any whither and to skull and steer himself as he pleas'd the other part L seem'd to be as 't were the ninth division of his belly and had many single brisles on either side From the end V of which through the whole belly there was a kind of Gut of a darker colour MMM wherein by certain Peristaltick motions there was a kind of black substance mov'd upwards and downwards through it from the orbicular part of it N which seem'd the Ventricle or stomach to the tail V and so back again which peristaltick motion I have observ'd also in a Louse a Gnat and several other kinds of transparent body'd Flies The Thorax or chest of this creature OOOO was thick and short and pretty transparent for through it I could see the white heart which is the colour also of the bloud in these and most other Insects to beat and several other kind of motions It was bestuck and adorn'd up and down with several tufts of brisles such as are pointed out by P P P P the head Q was likewise bestuck with several of those tufts SSS it was broad and short had two black eyes TT which I could not perceive at all pearl'd as they afterwards appear'd and two small horns RR such as I formerly describ'd Schem XXVII The motion of it was with the tail forwards drawing its self backwards by the frisking to and fro of that tuft which grew out of one of the stumps of its tail It had another motion which was more sutable to that of other creatures and that is with the head forward for by the moving of his chaps if I may so call the parts of his mouth it was able to move it self downwards very gently towards the bottom and did as 't were eat up its way through the water But that which was most observable in this creature was its Metamorphosis or change for having kept several of these Animals in a Glass of Rain-water in which they were produc'd I found after about a fortnight or three weeks keeping that several of them flew away in Gnats leaving their husks behind them in the water floating under the surface the place where these Animals were wont to reside whil'st they were inhabitants of the water this made me more diligently to watch them to see if I could find them at the time of their transformation and not long after I observ'd several of them to be changed into an unusual shape wholly differing from that they were of before their head and body being grown much bigger and deeper but not broader and their belly or hinder part smaller and coyl'd about this great body much of the fashion represented by the prick'd line in the second Figure of the 27. Scheme the head and horns now swam uppermost and the whole bulk of the body seem'd to be grown much lighter for when by my frighting of it it would by frisking out of its tail in the manner express'd in the Figure by BC sink it self below the surface towards the bottom the body would more swiftly re-ascend then when it was in its former shape I still marked its progress from time to time and found its body still to grow bigger and bigger Nature as it were fitting and accoutring it for the lighter Element of which it was now going to be an inhabitant for by observing one of these with my Microscope I found the eyes of it to be altogether differing from what they seem'd before appearing now all over pearl'd or knobb'd like the eyes of Gnats as is visible in the secong Figure by A. At length I saw part of this creature to swim above and part beneath the surface of the water below which though it would quickly plunge it self if I by any means frighted it and presently re-ascend into its former posture after a little longer expectation I found that the head and body of a Gnat began to appear and stand cleer above the surface and by degrees it drew out its leggs first the two formost then the other at length its whole body perfect and entire appear'd out of the husk which it left in the water standing on its leggs upon the top of the water and by degrees it began to move and after flew about the Glass a perfect Gnat. I have been the more particular and large in the relation of the transformation of divers of these little Animals which I observ'd because I have not found that any Author has observ'd the like and because the thing it self is so strange and heterogeneous from the usual progress of other Animals that I judge it may not onely be pleasant but very usefull and necessary towards the compleating of Natural History There is indeed in Piso a very odd History which this relation may make the more probable and that is in the 2. Chapter of the 4. Book of his Natural History of Brasil where he says Porro praeter tot documenta fertilitatis circa vegetabilia sensitiva marina telluris aemula accidit illud quod paucis à Paranambucensi milliaribus piscatoris uncum citra intentionem contingat infigi vadis petrosis loco piscis spongia coralla aliasque arbusculas marinas capi Inter haec inusitatae formae prodit spongiosa arbuscula sesquipedis longitudinis brevioribus radicibus lapideis nitens
vanish which by directing a small Telescope towards that part they appear'd and disappeard in I could presently find to be indeed small Starrs 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 now and then in several parts of the constellation could perceive little twinklings of Starrs making a very short kind of apparition and presently vanishing but noting diligently the places where they thus seem'd to play at boe-peep I made use of a very good twelve foot Tube and with that it was not uneasie to see those and several other degrees of smaller Starrs and some smaller yet that seem'd 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 observ'd some twelve several magnitudes of Starrs less then those of the six magnitudes commonly recounted in the Globes It has been observ'd and confirm'd by the accuratest 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 whil'st the Moon has been in an Eclipse I shall not here 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 then it is hitherto generally believ'd I have further taken notice that not onely the Sun Moon and Starrs and high tops of mountains have suffer'd 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 tremulation of the Trees and Bushes as well as of the edges of the Sun Divers of these Phaenomena 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 parly also false Setting my self therfore upon the inquiry of these Phaenomena I first endeavour'd to be very diligent in taking notice of the several particulars and circumstances observable in them and next in making divers particular Experiments that might cleer some doubts and serve to determine confirm and illustrate the true and adaequate cause of each and upon the whole I find much reason to think that the true cause of all these Phaenomena 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 caus'd by any terminating superficies of the Air above nor from any such exactly defin'd superficies within the body of the Atmosphere This Conclusion is grounded upon these two Propositions First that a medium whose parts are unequally dense and mov'd by various motions and transpositions as to one another will produce all these visible effects upon the Rays of light without any other coefficient cause 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 divers mutations and positions one to another By Density and Rarity I understand a property of a transparent body that does either more or less refract a Ray of light coming obliquely upon its superficies out of a third medium toward its perpendicular As I call Glass a more dense body then Water and Water a more rare body then 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 superficies So as to the business of Refraction spirit of Wine is a more dense body then 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 00 in both those Mediums the angle of incidence in Water was but 41° 3 ' 5. but the angle of the incidence in the trial with spirit of Wine was 42° 45 ' But as to gravity Water is a more dense body then spirit of Wine for the proportion of the same Water to the same very well rectify'd spirit of Wine was as 21. to 19. So as to Refraction Water is more Dense then Ice for 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 then that of Ice though some considerable Authors have affirm'd the contrary and though the Ice be a very hard and the Water a very fluid body That the former of the two preceding Propositions is true may be manifested by several Experiments As 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 Fresh almost any kind of Salt dissolv'd in Water and filtrated so that it be cleer spirit of Wine and Water nay spirit of Wine and spirit of Wine one more highly rectify'd then the other and very many other liquors if I say you take any two of these liquors and mixing them in a Glass Viol against one side of which you have fix'd or glued a small round piece of Paper and shaking them well together so that the parts of them may be somewhat disturb'd and move up and down you endeavour to see that round piece of Paper through the body of the liquors you shall 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 onely that the mutations here are much quicker And if in steed 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 Starrs though much quicker which two Phaenomena for I shall take notice of no more at present though I could instance in multitudes of others must necessarily be causd by an inflection of the Rays 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 chang'd 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 light is hindred from proceeding in a streight line and inflected or deflected by a curve
of Venice Looking-glass The description of them Obser. 29. Of the Seeds of Time A description of them A digression about Natures method Observ. 30. Of Poppy Seeds The description and use of them Observ. 31. Of Purslane Seeds A description of these and many other Seeds Observ. 32. Of Hair The description of several sorts of Hair their Figures and Textures the reason of their colours A description of the texture of the skin and of Spunk and Sponges by what passages and pores of the skin transpiration seems to be made Experiments to prove the porousness of the skin of Vegetables Observ. 33. Of the Scales of a Soale A description of their beauteous form Observ. 34. Of the Sting of a Bee A description of its shape mechanisme and use Observ. 35. Of Feathers A description of the shape and curious contexture of Feathers and some conjectures thereupon Obser. 36. Of Peacocks Feathers A description of their curious form and proprieties with a conjecture at the cause of their variable colours Obser. 37. Of the Feet of Flyes and other Insects A description of their figure parts and use and some considerations thereupon Obser. 38. Of the Wings of Flyes After what manner and how swiftly the wings of Insects move A description of the Pendulums under the wings and their motion the shape and structure of the parts of the wing Obser. 39 Of the Head of a Fly 1. All the face of a Drone-fly is nothing almost but eyes 2. Those are of two magnitudes 3. They are Hemispheres and very reflective and smooth 4. Some directed towards every quarter 5. How the Fly cleanses them 6. Their number 7. Their order divers particulars observ'd in the dissecting a head That these are very probably the eyes of the Creature argued from several Observations and Experiments that Crabs Lobsters Shrimps seem to be water Insects and to be framed much like Air Insects Several Considerations about their manner of vision Obser. 40. Of the Teeth of a Snail A brief description of it Observ. 41. Of the Eggs of Silk-worms Several Observables about the Eggs of Insects Observ. 42. Of a blue Fly A description of its outward and inward parts It s hardiness to indure freezing and steeping in Spirit of wine Observ. 43. Of a water Insect A description of its shape transparency motion both internal and progressive and transformation A History somewhat Analogus cited out of Piso. Several Observations about the various wayes of the generations of Insects by what means they act so seemingly wisely and prudently Several Quaeries propounded Postscript containing a relation of another very odd way of the generation of Insects An Observation about the fertility of the Earth of our Climate in producing Insects and of divers other wayes of their generation Observ. 44. Of the tufted Gnat. Several Observables about Insects and a more particular description of the parts of this Gnat. Ob. 45. Of the great belly'd Gnat. A short description of it Obser. 46. Of a white Moth. A description of the feathers and wings of this and several other Insects Divers Considerations about the wings and the flying of Insects and Birds Obs. 47. Of the Shepherd Spider A description of its Eyes and the sockets of its long legs and a Conjecture of the mechanical reason of its fabrick together with a supposition that 't is not unlikely but Spiders may have the make of their inward parts exactly like a Crab which may be call'd a water Spider Obser. 48. Of the hunting Spider A short description of it to which is annext an excellent History of it made by Mr. Evelyn Some further Observations on other Spiders and their Webs together with an examination of a white Substance flying up and down in the Air after a Fog Obser. 49. Of an Ant. That all small Bodies both Vegetable and Animal do quickly dry and wither The best remedy I found to hinder it and to make the Animal lye still to be observ'd Several particulars related of the actions of this Creature and a short description of its parts Obs. 50. Of the wandring Mite A description of this Creature and of another very small one which usually bore it company A Conjecture at the original of Mites Observ. 51. Of a Crab-like Insect A brief description of it Observ. 52. Of a Book-worm A description of it where by the way is inserted a digression experimentally explicating the Phaenomena of Pearl A consideration of its digestive faculty Observ. 53. Of a Flea A short description of it Observ. 54. Of a Louse A description of its parts and some notable circumstances Observ. 55. Of Mites The exceeding smalness of some Mites and their Eggs. A description of the Mites of Cheese and an intimation of the variety of forms in other Mites with a Conjecture at the reason Ob. 56. Of small Vine-Mites A description of them a ghess at their original their exceeding smalness compar'd with that of a Wood-louse from which they may be suppos'd to come Observ. 57. Of Vinegar-worms A description of them with some considerations on their motions Obs. 58. Of the Inflection of the Rays of Light in the Air. A short rehearsal of several Phaenomena An attempt to explicate them the supposition founded on two Propositions both which are indeavoured to be made out by several Experiments What density and rarity is in respect of refraction the refraction of Spirit of Wine compared with that of common Water the refraction of Ice An Experiment of making an Vndulation of the Rays by the mixing of Liquors of differing density The explication of inflection mechanically and hypothetically what Bodies have such an inflection Several Experiments to shew that the Air has this propriety that it proceeds from the differing density of the Air that the upper and under part of the Air are of differing density some Experiments to prove this A Table of the strength of the spring of the Air answering to each degree of extension when first made and when repeated Another Experiment of compressing the Air. A Table of the strength of the Air answering to each compression and expansion from which the height of the Air may be suppos'd indefinite to what degree the Air is rarifi'd at any distance above the Surface of the Earth how from this Inflection is inferr'd and several Phaenomena explain'd That the air near the Earth is compos'd of parts of differing density made probable by several Experiments and Observations how this propriety produces the effects of the waving and dancing of Bodies and of the twinkling of the Stars Several Phaenomena explicated Some Quoeries added 1. Whether this Principle may not be made use of for perfecting Optick Glasses What might be hoped from it if it were to be done 2. Whether from this Principle the apparition of some new Stars may not be explicated 3. Whether the height of the Air may be defin'd by it 4. Whether there may not sometimes be so great a disparity of density between