Munday,March12. 1665/6.
Observations continued upon theBarometer, orBallance of the Air. A Relation concerning theEarth-quakeneerOxford; together with some Observations of the sealedWeatherglassandBarometerthereupon byDr. Wallis. A more full and particular Account of those Observations aboutJupiter, that were mention'd in Numb. 8. An Account of some Books, lately publisht,videl.Mr.BoylesHydrostatical Paradoxes;Stenode Musculis & Gladulis;De Graeffde Natura & Usu Succi Pancreatici.
Observations continued upon theBarometer, orBallance of the Air. A Relation concerning theEarth-quakeneerOxford; together with some Observations of the sealedWeatherglassandBarometerthereupon byDr. Wallis. A more full and particular Account of those Observations aboutJupiter, that were mention'd in Numb. 8. An Account of some Books, lately publisht,videl.Mr.BoylesHydrostatical Paradoxes;Stenode Musculis & Gladulis;De Graeffde Natura & Usu Succi Pancreatici.
TheseTransactionsbeing intended,not onlyto be (by parcels) brief Records of the Emergent Works and Productions in the Universe; Of the Mysteries of Nature of later discoveries; And, of the growth of Useful Inventions and Arts;butalso, and chiefly, to sollicite in all parts mutuall Ayds and Collegiate endeavours for the farther advancement thereof: We shall begin thisSecondyear of our Publications in this kind (in which, for 3-moneths the Printing-presses were interrrupted by the publick Calamity) with a few more particular Observations upon theBallance of the Air, as they are most happily invented and directed by Mr.Boyle; and deserve to be prosecuted with care and diligence in all places.
But it is to be premised, that the Worthy person, who was alledged as the Author of the Observations, delivered of this kind in the last of theseTracts(Dr.Beale) gives notice, Thathe did not pretend to exactness, but only to excite the carefulness of others in the several distant places, and chiefly such, as can have the assistance of aWheel-ballanceperfectly filled: without both which aids he hopes not to obtain all the benefits and mysteries of this Invention.
This being thus briefly intimated, the Account of the Observations themselves, as they were extracted out of a late Letter of the same Person, are, as followes:
1. As I have fitted and filled theSingle Cane, I can say in the general, That I have not yet found any such infallible Prognostick of these changes of weather, which do follow a long serenity, or setled weather. And perchance in brighter Climats it may be constantly infallible. In theseNorthern Islands, the Clouds are so short, and narrow, and by fickle changes are sometimes emptied upon us, sometimes so neer, as may make so little variation in the weight of the whole Atmosphere of Air, as may sometimes deceive us, or smother and hide from us theHygroscopesare Instruments, to discover the degrees of Moisture and Drought of the Air.causes of fixedness, or of changes. I wish I could see a goodCalendarorJournaltaken in taken inTangier, and in some of ourNorthernand mostSouthernparts ofAmerica. I have store ofHygroscopesof divers kinds; and I do remark them, and the sweatings of Marble, and as many other famed Prognosticks, as I can hear off; but can find nothing so neerly indicative of the change of weather, as thisBallance. Those others are often changed by Dews, which do not at all alter theBallance, nor alter the state of the weather: And the open Weather-glass is known to signifie nothing at certainty, having a double obedience to two Masters, sometimes to theWeight of the Air, sometimes toHeat, as the service is commanded.
2. And in further confirmation of this Note, I may adde to the former, That inJanuarylast 1665/6, from thefourth, and more especially from theseventhday, for many daies it continued very dark, so that all men expected daily great rain; yet theMercuryheld very high, neer to the greatest height; And though in those daies sometimes thick mists arose, and some small rain fell, yet theQuick-silverheld at a great height: which did indicate to me, there couldthenbe no great change of weather. As the small rain fell, it yeilded somewhat, not much; and that does moreconfirm the indication. And more lately, in very dark daies, I had the same confidence upon the same ground, and I was not disappointed.
3. Again, if theMercuryascends to a good height after the fall of rain (as sometimes, but less often it does) then I look for a setled serenity; but if it proceeds after rain in a descending motion, then I expect a continuance of broken and showry weather. But in all, as I only say,For the most part, so I dare not positively declare it an affirmative result, but do refer it to the remarks of others. And this may explicate the Notes 6. and 14 ofNum.9. into more clearness.
4. That we find the Weather and our Bodies more chill, cold, and drooping, when theMercuryis lowest, and the Air lightest, besides other causes, I guess, That as Air is to us the breath of life, as water is to Fishes; so, when we are deprived of the usual measure of this our food, 'tis the same to us, as when the water is drawn ebb from Fishes. But I would much rather be instructed by others, then offer much in this kind.
5. The lowest descent of theMercuryin all the time, since I have observed it, wasOctob.26. 1665. in the Evening, when it was very near at 27½ Inches. Which I find thus circumstanced with the weather in my notes.
Oct.25. Morning;Mercuryat 28½ Inch. Great storms and much rain.Oct.26. Morning;Merc.at 28. winds quiet, thick dark clouds.Oct.26. Evening;Merc.at 27½. That day, and some daies following, the weather was variable, frequent rain, and as you see, theMercurylower, than usual.
Oct.25. Morning;Mercuryat 28½ Inch. Great storms and much rain.
Oct.26. Morning;Merc.at 28. winds quiet, thick dark clouds.
Oct.26. Evening;Merc.at 27½. That day, and some daies following, the weather was variable, frequent rain, and as you see, theMercurylower, than usual.
6. Over the place, where thisMercurial Canestands, I have set aWind vane, with purpose of exactness, of a Streamer in Brass so large, and pointing to a Board indented in the Margin, that I can at a sure Level upon theVane, take every of the 32. points of the Wind, half points, and quarter points, at good distance. Otherwise we may find our guesses much deceived, as the best guessers, upon trial, do acknowledge. And this exactness may become theWheel-ballance, which shews the minutest variations almost beyond imagination. And thus any servant, at the approach of a thick Cloud, or otherMeteor, higher or lower, or at the rising of a storm or fresh wind in the night, or day, may bring a report of the Weight of the Air, as certainly and almost aseasily, as of the Sun from theDialin a Sunshine. It were good to have anIndexof Winds, that discover'd as well their Ascent and Descent, as their Side-coastings.
This Relation was communicated by the excellently learned Dr.Wallis, as follows:
On the 19. ofJanuary1665.Stylo Angliæ(orJan.29. 1666.stylo novo) at divers places neerOxford, was observed a smallEarthquake(as atBlechington, Stanton-St. Johns, Bril, &c.) towards evening. InOxfordit self, I doe not hear, that it was observ'd to be an Earthquake; yet I remember about that time (whether precisely then or not; I cannot say) I took notice of some kind of odde shaking or heaving I observed in my study, but did impute it to the going of Carts or Coaches, supposed to be not far off; though yet I did take notice of it, as a little differing from what is usual on such occasions; (and wondered the more, that I did not hear any:) But not knowing, what else to refer it to, I thought no more of it. And the like account I have had from some others inOxford, who yet did not think of an Earth-quake; it being a rare thing with us. Hearing afterwards of an Earthquake observed by others; I looked on my Notes concerning myThermoscopeandBaroscope, to see if any alteration considerable had then happened.
MyThermoscopeconsists of a round large Glass, containing about half a pint or more; from whence issues a long Cylindrical neck of Glass, about two foot and a half in length, and less than a quarter of an inch diameter; which neck washermeticallysealed at the top, to exclude communication with the External Air; but before the sealing of it, the whole Glass was filled withSpirit of Wine(tinged withCochineel, to make it the more discernable to the Eye) so warmed, that it filled the whole content of the Glass; but afterwards, as it cooled, did so subside, as to leave a void space in the upper part of the Neck. Which Instrument, so prepared, doth by the rising or falling of the tinged liquor in the neck (consequent upon the expanding or contracting of the whole liquor contained in it and the Ball below) give a very nice account of the Temperature of the Air,as toHeatorCold: Even so nice, as that my being or not being in my Study I find to vary its hight sometimes almost a quarter of an inch.
MyBaroscope, I call another Instrument for estimating theWeightorPressureof the Incumbent Air, consisting of a longGlass-tubeof about 4. foot in length, and about a quarter of an inch Bore: which tube (hermeticallysealed at the one end) being filled with Quicksilver (according to theTorricellianExperiment) is inverted, so as to have the open end of it immersed in Stagnant Quicksilver, contained in a larger Glass under it, exposed to the pressure of the outward Air: Out of which open end (after such immersion) the Quicksilver in the Tube being suffered to run out, as much as it will, into the Stagnant Quicksilver, in which that mouth or open end is immersed, there is wont to remain (as is commonly known to those acquainted with this Experiment) a Cylinder of Quicksilver suspended in the Tube, about 28, 29, or 30. inches high; measuring from the surface of the Stagnant Quicksilver perpendicularly; (but more or less, within such limits, according as the Weight or Pressure of the Air incumbent on the External Stagnant Quicksilver exposed to it, is greater or less:) leaving the upper part of the Tube void. (Both which Instruments being the contrivance of the HonourableRobert Boyle, they are by him more particularly described in hisPhysico-Mechanical Experiments touching the Air, Exper.17. and 18. and in hisThermometrical Discourses, premised to hisHistory of Cold.)
Now, according to both these Instruments, having kept a dailyRegisterof Observations for more than a whole year (saving when I have been for some short time absent from home) I find my Notes for that day to be these.
So that, there being in the morning (January19.) a hard frost (which began the day before about 4. of the Clock in theafternoon (Jan.18.) and continued (with us) till about 5. of the Clock in the afternoon of that day,Jan19. with some fierceness) and the weather,Jan.19. being in the morning, close; and cloudy all the day, with little of Sun-shine; the Liquor in theThermoscopewas very little raised, by 4. of the Clock afternoon, that is, but5/16of an inch (which, had the Sun shone, would, it's likely, have been near an Inch:) and after that time (or somewhat before) had there been no considerable change of weather, it would upon the Sun's setting have fallen (and probably so it did, till about 5. of the Clock, though I took no Observation in the interim.) But, contrary to what would have been expected, it was at 9. of the Clock at night, higher by ⅛ of an inch, than it had been at 4. occasioned by the change of weather, the Frost suddenly breaking, with us, between 5. and 6. of the Clock; about which time also it began to rain, and continued raining that Evening and good part of the Night. And the next morning I found the Liquor yet higher by half an inch,vid.15¼ inches: (by reason of the Air that night being so much warmer, than it had been the day before;) whereas commonly it is considerably lower in the morning, than over night.
As to theBaroscope, for the Weight or Pressure of the Air; I find, that for the 11, l2, 13, 14, 15, 16, and 17. dayes, theMercuryin the Tube, was (by the ballancing Pressure of the incumbent Air on the stagnant Quicksilver, exposed to it) kept up to the height of near 30. Inches above the surface of the External Quicksilver, (though with some little variation, as 30, 2915/16, 29⅞, 2913/16but never so low, all that time, as 29¾;) which is the greatest height I have know it at, (for I do not find that I have ever, till then, observed it to be, in my Glasses, full 30. Inches, though it have been very near it:) the Weather having been almost continually Foggy, or very thick Mists, all that time.January18. it came down to 29¾, in the forenoon; and afternoon, to 2911/16. about the time the frost began: AndJan.19. it was, at 8. in the morning, come down to 29½; at 4. in the afternoon, to 29¼. But at 9. in the evening (when the Earth quake had intervened) it was risen half an inch,vid.to 29¾. And, by the next morning, fallen again a whole inch,vid.to 28¾; which fall I attribute (at least in part) to the rain that fell in the night.
This being what I observed out of myRegisterof these Instruments, (which, if I had then thought of an Earthquake, Ishould have more nicely watched) what I have further gathered from Reports, is to this purpose.
I hear, it was observed atBlechington, above 5. miles to theNorthofOxford, and so along byBostol,Horton,Stanton-St. Johns, and so towardsWhately, which is about 4. milesEastwardfromOxford. Not at all these places at the same time, but moving forward fromBlechingtontowardsWhately. For it was atStantonabout 6. of the Clock or later (as I understand from Mr.Boyle, who was there at that time;) but had been atBlechingtona good while sooner. And I am told, that it was taken notice of by DoctorHolder(a Member of ourSociety) who was then atBlechington, to be observed by those in the further part of the Garden, some very discernable time before it was observed by those in the House; creeping forward from the one place to the other. What other places in the Country it was observed at, I have not been informed: but atOxford(which, it seems, was about the skirts of it) it was so small, as would have been hardly noted at all, had not the notice, taken of it abroad, informed us of it.
Upon this Occasion, it will not be unseasonable to give some General accounts of what I have in myThermoscopeandBaroscopeobserved.
MyThermoscope, being fitted somewhat at adventures, I have found at the lowest to be somewhat more than 12. inches high, in the fiercest time of the long Frost in the beginning of the last year 1665. and about 27. Inches high, at the highest, in the hottest time of the last Summer: (which I mention, that it may appear at what temperature in proportion, the Air was at the time above-mentioned.) But I must add withall, that this standing so, as never to be exposed to the Sun, but in a room, that has a window only to the North, it would have been raised much higher than 27. inches, if it were put in the hot Sun-shine in Summer; this, as it is placed, giving therefore an account onely of the Temperature of the Air ingeneral, not of the immediate heat of the Sun-shine.
This Instrument, thus situated, when it is about 15. inches, or lower, is for the most part hard frost; but seldom a frost, if higher than 16. Yet this I have often observed, that the Air by theThermoscopehas appeared considerably colder (and the liquor lower) at sometimes when there is no Frost, than at some other times, when the Frost hath been considerably hard.
In myBaroscope, I have never found the Quicksilver higher than 30. inches, nor lower than 28. (at least, scarce discernably, not1/16of an inch higher thanthat, or lower thanthis;) which I mention, not only to shew the limits, within which I have observed mine to keep,vid.full 2 inches, but likewise as an Estimate of the Clearness of the Quicksilver from Air. For, though my Quicksilver were with good care cleansed from the Air; yet I find that which Mr.Boyleuseth, much better: for, comparing his with mine at the same times, and both inOxford, at no great distance; I find his Quicksilver to stand alwaies somewhat higher than mine (sometimes neer a quarter of an Inch;) which I know now how to give a more probable account off, than that my Quicksilver is either heavier than his; or else, that his is better cleansed from Air, (unless, possibly, the difference of the Bore, or other circumstances of the Tube, may cause the alteration; mine being a taller Tube, and a bigger Bore, than his.) And upon like reason, as his stands higher than mine; so another less cleansed from Air, may at the same time be considerably lower, and consequently under 28. Inches at the lowest.
Inthick foggyweather, I find my Quicksilver to rise; which I adscribe to the heaviness of the Vapours in the Air. And I have never found it higher, than in the foggy weather above-mentioned.
InSunshinyweather it riseth also (and commonly the clearer, the more;) which, I think, may be imputedpartlyto the Vapors raised by the Sun, and making the Air heavier; andpartlyto the Heat, increasing the Elastick or Springy power of the Air. Which latter I the rather add, because I have sometimes observed in Sunshiny weather, when there have come Clouds for some considerable time (suppose an hour or two) the Quicksilver has fallen; and then, upon the Suns breaking out again, it has risen as before.
InRainyweather, it useth to fall (of which the reason is obvious, because the Air is lightned, by so much as falls:) InSnowyweather, likewise, but not so much as inRain. And sometimes I have observed it, upon aHoar-frost, falling in the night.
*The Author of these Observations intends hereafter more particularly to observe,from what pointsthose Winds blow, that make the Quicksilver thus subside.
ForWindyweather, I find itgenerallyto fall; and that more universally, and more discernably, than upon Rain: (which I attribute to the Winds moving the Aircollaterally, and thereby not suffering it to press so muchdirectlydownwards: the like ofwhich we see in swimming, &c.) And I have never found it lower than in high Winds.*
I have divers times, upon discerning my Quicksilver to fall without any visible cause at home, looked abroad; and found (by the appearance of broken Clouds, or otherwise) that it had rained not far off, though not with us: Whereupon, the Air being then lightened, our heavier Air (where it rained not) may have, in part, discharged it self on that lighter.
Since the publishing ofNumb.8. of theseTransactions, where, among other particulars, some short Observations were set down touching both theshadowof one ofJupiter's Satellits, passing over his Body, and thatPermanent Spot, which manifests the Conversion of that Planet about his ownAxis; there is come to hand anExtractof that Letter, which was written fromRome, about those Discoveries, containing an ample and particular Relation of them, as they were made by the LearnedCassini, Professor ofAstronomyin the University ofBononia. ThatExtract, as it is found in theFrench Journal des ScavansofFebr.22. 1666. we thusEnglish.
MonsieurCassini, after he had discovered (by the means of those Excellent Glasses of 50.palmes, or 35.feet, made by M.Campani) theShadows, cast by the 4 Moons orSatellitsofJupiterupon his Diske, when they happen to be between the Sun and Him; after he had also distinguished their Bodiesuponthe Diske ofJupiter; made the last year some Prædictions for the Months ofAugustandSeptember, noting the dayes and hours, when the Bodies of the saidsatellitsand theirShadowsshould appear uponJupiter, to the end that the Curious might be convinced of this matter by their own Observations.
Some of these Prædictions have been verified not only atRome, and in other places ofItaly, but also atParisby M.Auzout, the most Celebrated and the most Exact of ourAstronomers; and inHolland, by M.Hugens. And we can now doubt no longer, of the rotation of theSatellitsaboutJupiter, as the Moon turns about the Earth; nor believe, thatJupiteror hisAttendantshave any other Light, than that, which they receive from the Sun; as some didassure before these Observations. There remained to find by Experience, whetherJupiterdid turn about hisAxis, as many believe, that theEarthturns about her's. And although mostAstronomershad conjectur'd, it did so, either by this Analogy, or by other Congruities, yet it was much wish'd, that we might be assured thereof by Observations. And this it is, for which we are obliged to M.Cassini, who, having by the advantage of the same Glasses discover'd several changes, as well in the three obscureBelts, commonly seen inJupiter, as in the rest of hisDiske, and having also observed Spots in the midst of thatPlanet, and sometimesBrightnesses, such as have bin formerly seen in theSun, hath at length discover'd aPermanent Spotin theNorthernpart of the mostSouthernBelt; by the means whereof, he hath concluded, thatJupiterturns about hisAxisin 9.hours, 56. minutes, and makes 29. whole circumvolutions in 12 dayes 4. minutes of ours, and 360 in 149. dayes. For he has found, that thisSpotwas not caused by the Shadow of anySatellit, as well by reason of its Situation, as because it appeared, when there could be no Shadow. Besides, that its motion differed from that of the Shadows, which is almost equal, as well towards the Edges as towards the Middle ofJupiter: Whereas, on the contrary, thisSpothath all the accidents, that must happen to a thing, which is upon the surface of a round Body moving; for example, to move much more slowly towards the Edges, than towards the Middle, and to pass over that part, which is in the middle of the Diske, equal to the half of theDiameter, in the sixth part of the time, it takes to make the whole revolution: he having seen this half pass'd over, in 99 or 100 minutes just, as it must happen, supposing the whole circumrotation is made in 9. hours 56. minutes.
He hath not yet been able to determine the Situation of theAxis, upon which this motion is made, because theBelts, according to which it is made, have for some years appeared streight, though in the precedent years, otherAstronomershave seen them a little crooked: Which sheweth, that theAxisof the diurnal motion ofJupiteris a little inclined to the plain of theEcliptick. But in time we may discover, what certainty there is in this matter.
TheseTablesare not yet sent over, but, 'tis hoped, will be, ere long.
After this excellent Discovery, he hath calculated manyTables, whereof he gives the Explication and Use in the Letters by him addressed to the AbbotFalconieri. By the means of them, one may know,whenthisSpotmay be seen by us. For, having firstconsidered it in relation to theSun, in respect whereof, its motion is regular, he considers the same in relation to theEarth, whereWeobserve it; and shews by the means of hisTables, what is to be added or subtracted, to know, at what time the saidSpotis to come into the middle ofJupiter's Diske, according as he is Oriental or Occidental. He hath also considered it in relation to an unmovable point, which he has supposed to be the first point ofAries, because we thither refer here upon Earth the beginning of all the Celestial motions, andthereis thePrimum mobile, that one would imagine, if we were inJupiter, as we do here imagine Ours of 24. hours.
The Discovery is one of the best, that have been yet made in the Heavens; and those, that hold the Motion of the earth, find in it a full Analogy. For,Jupiterturning about the Sun, does nevertheless turn about hisAxis; and although he be much bigger than the Earth, he does nevertheless turn much more swiftly than it, since he makes more than two Turns, and a third part, for its one; and carries with him 4. Moons, as the Earth does one.
This Observation ought to excite all Curious persons to endeavour the perfecting ofOptick Glasses, to the end that it may be discovered, whether the otherPlanets, asMars,VenusandMercury, about whom no Moon hath as yet been discovered, do yet turn about theirAxes, and in how much time they do so; especiallyMars, in whom someSpotis discover'd, andVenus, wherein M.Burattinihath signified fromPoland, he has observ'd Inequalities, as in the Moon.
It will be worth while, to watch for the seeing ofJupiteragain this Spring, that this happy Observation may be confirmed in divers places, and endeavours used to make new ones.
I.Hydrostatical Paradoxes, made out by New Experiments (for the most part Physical, and Easie) by the Honourable Robert Boyle.This Treatise, promised inNumb.8. of these Papers, is now come forth: And was occasioned by the perusal of the Learned MonsieurPaschallsTract,Of the Æquilibrium of Liquors, and of theWeight of the Air: Of which two Subjects, thelatterhaving been more clearly made out inEnglandby Experiments, which could not be made by MonsieurPaschaland others, that wanted the advantage of such Engines and Instruments, as have here been frequently made useoff; Our Noble Author insists most upon giving us his thoughts of the former,videl.theÆquilibrium of Liquors: Which Discourse consisting partly ofConclusions, and partly ofExperiments, theformerseem to Him to be almost all of them consonant to the Principles and Laws of theHydrostaticks; but as for thelatter, the Experimental proofs, offered by M.Paschallfor his Opinions, are by our Author esteemed such, that he confesses, he hath no mind to make use of them: for which he alledges more reasons than one; which, doubtless, will appear very satisfactory to IntelligentReaders.
Wherefore, instead of the thosePaschalianExperiments, there is in thisTreatisedeliver'd a far more Expeditious way, to make out,not onlymost of theConclusions, agreed on these two Authors,butothers also, that MPaschallmentions not: and that with so much more ease and clearness, that persons, but ordinarily versed in the common principles ofHydrostaticks, may readily apprehend, what is deliver'd, if they will but bring with them a due Attention, and Minds disposed to prefer Reason and Experience to Vulgar opinions and Authors.
It not being ourAuthorspresent Task, to deliver a Body ofHydrostaticks, but only someParadoxes, which he conceives to be proveable by his New way of making them out, he delivers them in as many distinct Propositions; after each of which, he endeavours, in a Proof, or an Explication, to show, both that it is true, and why it ought to be so.
TheParadoxesthemselves (after a premisedPostulatum) are these:
1. That in Water, and other Fluids, the Lower parts are pressed by the Upper.
2. That a lighter Fluid may gravitate or weigh upon a heavier.
3. That, if a Body, contiguous to the Water, be altogether, or in part, lower than the highest level of the said Water, the lower part of the Body will be pressed upward by the Water, that touches it beneath.
4. That in the Ascension of Water in Pumps, &c. there needs nothing to raise the Water, but a Competent weight of an External Fluid.
5. That the pressure of an External Fluid is able to keep an Heterogeneous Liquor suspended at the same height in several Pipes, though these Pipes be of very different Diameters.
6. If a Body be placed under Water, with its uppermost Surface parallel to the Horizon; how much Water soever there may be on this or that side above the Body, the direct pressure susteined by the Body (for we now consider not the Lateral nor the Recoyling pressure, to which the Body may be exposed, if quite environed with Water) is no more, than that of a Column of water, having Horizontal Superficies of the Body for its Basis, and the Perpendicular depth of the Water for its height.
And so likewise,
And so likewise,
If the Water, that leans upon the Body, be contained in Pipes open at both ends, the pressure of the Water is to be estimated by the weight of a pillar of Water, whose Basis is equal to the lower Orifice of the Pipe (which we suppose to be parallel to the Horizon) and its height equal to a perpendicular, reaching thence to the top of the Water; though the Pipe be much inclined towards the Horizon, or though it be irregularly shap'd, and much broader in some parts, than the said Orifice.
7. That a Body, immersed in a Fluid, sustains a Lateral pressure from the Fluid; and that increased, as the depth of the immersed Body, beneath the Surface of the Fluid, increaseth.
8. That Water may be made as well to depress a Body lighter than it self, as to buoy it up.
9. That, whatever is said of Positive Levity, a parcel of Oyl lighter than Water, may be kept in Water without ascending in it.
10. That the cause of the Ascension of Water in Syphons, and of its flowing through them, may be explicated without having a recourse to Nature's abhorrency of aVacuum.
11. That a Solid Body, as ponderous as any yet known, though near the Top of the water it will sink by its own weight; yet if it be placed at a greater depth, than that of twenty times its own thickness; it will not sink, if its descent be not assisted by the weight of the incumbent Water.
These are theParadoxes, evinced by our Authour with much evidence and exactness, and very likely to invite Ingenious men to cultivate and to make further disquisitions in so excellent a part of Philosophy, as are theHydrostaticks; and Art deserving greatElogiums, not only, upon the account of theTheoremsandProblems, which are most of them pure and handsome productions of Reason, very delightful and divers of them surprising, and besides, much conducing to the clear explication andthorow-understanding of many both familiar and abstrusePhænomenaof Nature; but also, upon the score of itsPracticaluse, since the Propositions, it teaches, may be of great importance to Navigation, and to those that inquire into the Magnitudes and Gravities of Bodies, as also to them, that deal in Salt-works: Besides, that theHydrostaticksmay be made divers waies serviceable toChymists, as the Author intimates, and intends to make manifest, upon several occasions, in his yet unpublisht part of theUsefulness of Natural and Experimental Philosophy.
These Propositions are shut up by two importantAppendixes, whereof theonecontains an Answer to seven Objections by a late learned Writer, to evince, that the upper parts of water press not upon the lower; theother, solves that difficultproblem, whyUrinatorsorDivers, and others, who descend to the bottom of the Sea, are not oppressed with the weight of the incumbent water? where, among other solutions,thatis examined, which occurs in a printed Letter of Monsieurdes Cartes, but is found unsatisfactory.
II.Nicolai Stenonis de Musculis & Glandulis Observationum Specimen; cum duabus Epistolis Anatomicis. In theSpecimenit self, the Author, having described ingeneral, both theStructureand theFunctionof theMuscles, applies that description to theHeart, to demonstrate thatthatis also atrue Muscle: Observingfirst, that in the substance of theHeartthere appears nothing butArteries, Veins, Nerves, Fibres, Membrans; and that that, & nothing else is found in aMuscle; affirming withall, that which is commonly taught of theMuscles, and particularly of theHeart's Parenchyma, as distinct fromFibres, is due, not to theSenses, but theWitofAnatomists: so that he will not have theHeartmade up of a substance peculiar to it self, nor considered as the principle ofInnate heat, or ofSanguification, or ofvital spirits. He observesnext, that theHeartperforms the likeoperationwith theMuscles, to wit, to contract the Flesh; which action how it can have a different cause from that of the Contraction made in theMuscles, where there is so great a parity and agreement in theVessels, he sees not. And as for thePhænomena, that occur, of theMotionof the Heart, he undertakes to explicate them all, from theDuctusorPositionof theFibres; but refers for the performance of this undertaking to anotherTreatise, he intends to publish.
ConglobateGlanduls are called those, that do consist, as it were, of one continued substance, having anevensuperficies; whereof there are many in theMesentery, and in other places: contra distinguisht to those, that bear the name ofConglomerateGlanduls, which are made up of several small Kernels, such as thePancreas, theSalivating Glanduls, &c.
As to his Observations aboutGlanduls, he affirms, that he has been the First, that has discover'd that Vessel, which by him is call'dSalivare Exterius, passing from theParotides(or the two chief Arteries that are on the right and left side neer the Throat) into the Mouth, and conveying theSpittle: Where he also gives an account of several other Vessels and Glanduls, some about theLips; others under theTongue; others in thePallate&c. To which he adds the Vessels of theEye-lids, which have their root in theGlandulsthat are about the Eyes, and serve for theshedding of Tears. He mentions also several things about theLymphatick vessels, and is of opinion, that the knowledge thereof may be much illustrated by that kind ofGlandulsthat are calledConglobatæ, and by theirtrueinsertion into the veins; the mistake of the latter whereof, he conceives to have very much misled the NobleLudovicus de Bills, notwithstanding his excellent method ofdissection. And here he observesfirst, that all theLymphatick vesselshave such a commerce with theGlanduls, that none of them is found in the body, which either has not its originefrom, or is insertedintoaGlandule: Andthen, thatGlandulsare a kind ofStrainers, so form'd, that whilst the Blood passes out of the Arteries into the Veins through the smallCapillaryvessels, theSerousparts thereof, being freed from theSanguineous, are by vertue of the beat expell'd through fit pores into theCapilariesof theLymphaticks, the direction of theNervesconcurring.
Of the two annex'dEpistles, theFirstgives an account of the dissection of twoRaja'sorSkates, and relates that the Author found in the bellies of these Fishes aHaddockof 1½ span long, and aSole, aPlaise, and nine middle-sizedSea crafishes; whereof not only the three former had their flesh, in the fishes stomack, turn'd into afluid, and the Gristles or Bones into asoftsubstance, but theCrafisheshad their shels comminuted into very small particles, tinging here and there theChylenear thePylorus; which he judges to be done not so much by the heat of the Fishes stomack, as by the help of some digesting juyce. Coming to theUterusof these Fishes, he takes occasion to examine, with what ground several famousNaturalistsandAnatomistshave affirm'd, that Eggs are theuterusexposed or ejected out of the body of the Animal. Taking a view of theirHeart, he there finds butoneventricle, and discourses of the difficulty arising from thence. As for theLungs, he saw no clearer footsteps of them in these, than he had done in other Fishes: but within the mouth he trac'd severalgaping fissures, and found the recesses of theGillsso form'd, that the water taken in at the mouth, being let out by these dores, cannot by them re-enter, by reason of a skin outwardly passing over every hole, and covering it. Where he intimates, that though Fishes have nottrueLungs, yet they want not aSuccedaneumthereto, to wit, theGills; and ifwatermay be to Fishes, whatAiris to terrestrial Animals, for Respiration: affecting, that whereas nothing is so necessary for the conservation of Animal life as a reciprocal Access and Recess of theAmbientto the sanguineous vessels, tis all one, whether that be done by receiving the Ambientwithinthe body, or by its gentle passingbytheProminentvessels of theGills.
The otherEpistle, contains some Ingenious Observations, touching the way, by which the Chicken, yet in the shell, is nourish't,videl.not by the conveyance of theYolkinto theLiverby theUmbilicalvessels, nor into theStomackby theMouth, but by a Peculiarductus, by him described, into theIntestins, where, according to his alledged experience, it is turn'd intoChyle: which he affirms, he hath discover'd, by taking an Egge from under a brooding Hen, when the Chicken was ready to break forth, and when he was looking for the passage of theYolk, out of its integument into theLiver, by finding it pass thence into theIntestins, as he found theWhiteto do by themouthinto thebelly. Whence he inclines to infer, that, since everyfætustakes in at the mouth the liquor it swims in, and since the Chicken receives thewhiteof the Egge into themouth, and theyolkby the new discover'dductusinto theIntestins, it cannot be certainly made out, that apartof theChyleis conveyed into theLiver, before it passes into theHeart; Exhorting in the mean time thePatronsof theLiver, that they would produce Experiments to evince their Ratiocinations.
III.Regneri de Graeff, de Succi Pancreatici Natura & usu, Exercitatio Anatomico-medica.In this Tract, the Industrious Author, after he has enumerated the various opinions ofAnatomistsconcerning the use of that kernelly substance; call'dPancreas(inEnglish, theSweetbred) endeavours to prove experimentally that thisGlandulewas not form'd by Nature, to separate anyExcrementitioushumor, and to convey it into theIntestins, but to prepare anusefuljuyce out of the Blood and Animal Spirits, of a somewhatAcidtaste, and to carry the same into the Gut, call'dDuodenum, to be there mixt with the Aliment, that has been in some degree already fermented in the Stomack, for a further fermentation, to be produced by the conflux of the said acidPancreatickjuyce and someBiliousmatter, abounding with volatile Salt, causing an Effervescence; which done, that juyce is, together with the purer part of the nourishment, carried into theMilkieveins, thence into thecommon receptacleof theChyleandLymphatick liquor, and so through theductus Thoracicusinto the right Ventricle of the Heart.
This Assertion, first advanced (saith theAuthor) partly byGothofredus Mobius, partly byFranciscus de le Boe Sylvius, he undertakes to prove by experiments; which, indeed, he has with much industry, tried upon several Animals, to the end that he might collect some of this juyce of thePancreasfor a taste: which having at last obtained, and found it somewhatacid, he thereupon proceeds to deliver his opinion both of theconstitutionand quantity of thisSuccusinhealthyAnimals, and the vices thereof, in theunhealthy: deriving most diseasespartlyfrom its too great Acidity, or from its saltness, or harshness;partlyfrom its paucity or redundancy: but especially, endeavouring to reduce from thence, as allintermittent Feavers(of all thePhænomenawhereof he ventures to assign the causes from thisHypothesis) so also theGout, Syncope's, Stranguries, Oppilations, Diarrhæas, Dysenteries, HystericalandColick passions, &c. All which he concludes with mentioning the waies and remedies to cure the manifold peccancy of this juyce by Evacuations and Alterations.
This seeming to be anewas well as aconsiderablediscovery, it is hop'd, that others will by this intimation be invited to prosecute the same by further experiments, either to confirm what this Author has started, if true, or to rectifie it, if he be mistaken.
InFig.1. ofNum.9 of these Tracts the Graver hath placed the bendedendof theSpringing WireC F, above theWire-stapleB, between it and theRingE, of theWeightD; whereasthatend should have been so expressed, as to passundertheWire-staple, betwixt its two Wires, into the saidRing.
London, Printed forJohn Martyn, andJames Allestry, Printers to the Royal Society. 1666.
Num.11.