Philosophical Transactions of the Royal Society Part 32

An _Intrument_ to measure the Strength of the Winde.

A large and good _needle_ shewing _Azimuths_ to degrees. {301}

_Thermometers_, _Barometers_, _Hygroscopes_.

These Observations being thought very considerable as well as curious, 'tis hoped, that those who have conveniency, will give encouragement and a.s.sistance for the making of them; and withall oblige the publick by imparting, what they shall have observed of this kind: The _Publisher_ intending, that when ever such observations shall be communicated to him, he will give notice of it to the _publick_, and take care of the improvement thereof to the best use and advantage. A _Pattern_ of the _Table_, proposed to be made for observing the _Tides_, is intended to be published the next opportunity, G.o.d permitting.

_An Account of Several Books lately published_

I. _Johannis Hevelii DESCRIPTIO COMETae, Anno aerae Christianae MDCLXV. exorti; una c.u.m MANTISSA Prodromi Cometici, Observationes omnes prioris COMETae MDCLIV, ex iisque genuinum motum accurate deductum, c.u.m Notis & Animadversionibus, exhibens._

This Book (as the t.i.tle it self intimates) undertakes two things. _First_, To give an Account of the _Second_ of the two late Comets, which appeared, when the _other_ was scarce extinct; Concerning which, the Author doth, from the Observations made by himself with a _s.e.xtant_ of 6 foot, and divided into _minutes_ and _seconds_, a.s.sign _both_ its true place (as well in respect of the _Ecliptick_ as the _aequator_) _and_ its proper motion; Adding a fair Delineation of its Course, together with the genuine Representations of its _Head_ and _Train_, in each day of its apparition; and subjoyning a General Description and Discourse of some of the more notable _Phenomena_ thereof. It was first seen at _Dantzick_ by the Watchmen, the 5th of _April_ st. n. 1665. and then observed by the _Author_ from _April_ 6, about 1 of the Clock in the morning, till _April_ 20 at 3.

in the morning. During which time, it went with a reasonable velocity; making 46 deg. in its...o...b.. _according to the Order of the Signs_, moving from the _Breast_ of _Pegasus_, towards the _Head_ of _Andromeda_, and the _Left Horn_ of _Aries_; having, as 'tis presumed, taken its rise from above _Sagittary_, and run through the _Breast_ of _Antinous_, under _Aquila_ and the _Dolphin_, to the said _Pegasus_; and so on, as is already expressed.

The _Head_ of it is in the Book described of a Colour like that of _Jupiter_, all along much brighter than that of the former Comet, though of a somewhat less magnitude; having in its middle onely _one_ round, but very bright and big _Kernel_ or Speck, resplendent like Gold, and encompa.s.sed with another more dilute and seemingly uniform matter: its _Tail_ being at first, about 17. deg. and afterwards 20. and sometimes 25 deg. long, and divaricated towards the End.

_Next_, it is observed, that though this Star did afterwards slacken its pace, yet it retained the vividness of its Colour, both of the _Head_ and _Train_; the _Head_ especially, keeping at the time as well of the last observations, as of the {302} first, the brightness of its single _kernel_, though the environing more dilute matter were then almost all lost; it being, according to the Author, more and more attenuated, and grown narrow, the nearer the Star approached to the Sun.

_Thirdly_, 'tis noted, That this _Comet_ did very much digress from the _Hypothesis_, delivered by _M. Auzout_, in regard that, whereas according to that _Hypothesis_, this Star should not arrive to the _Ecliptick_ till after the s.p.a.ce of 3 months, it arrived there the 28 of _April_. And then, that its first Conjunction with the Sun hapned between the 19 and 20 of _April_, and the second, the last of _April_, not (as _M. Auzout_, would have it) the 15 of _May_. So that he concludes, that this Comet never came down to the _Pleiads_ and the _Eye of Taurus_, as the Hypothesis of _M.

Auzout_ requires, but that from _April_ 20. it did immediately take its course towards the Ecliptick, deflecting every day more and more from the _Section_ of a _Great Circle_, to the _Lucida_ of _Aries_, arriving at the _Ecliptick_ the last of _April_, about the 8th or 10th deg. of _Taurus_; not in _July_ about the 8th of _Gemini_, and the _Eye of Taurus_.

_Fourthly_, He intimates, that if this Comet had appeared some weeks sooner, it would have confronted the former Comet, being yet in its vigour and of a conspicuous bigness, in the same place, where that was, viz. the _Head of Aries_.

_Fifthly_, He observes, that this Star in progress of time became _Retrograde_, whence it came to pa.s.s, that in the Months of _June_ and _July_ it did not appear again before the Rising of the Sun, though the Sun left it far behind: whereas, if it had proceeded toward the _Eye of Taurus_, it would have appeared again in the morning.

_Sixthly_, He maintains, that this Comet was not the same with the former; which he thinks may be demonstrated, onely by a due Delineation of both their Course upon the _Globe_; where he saith it to be evident, that the former could never come to the _Head_ of _Pegasus_, as moving already in _February_ in a streight Course about the _Head_ of _Aries_; Besides, that the _former_ went in the very beginning in a _Retrograde_ motion; but _this_ perpetually in a direct one: _that_, about the end, very slow, its Head lessning and growing dark; _this_ swift enough, with its head conspicuous and bright. To which he adds, that the whole Course of the former was made under a quite different _Angle_ of the _Orbite_ and _Ecliptick_, and a different Motion of the _Nodes_ from the latter: As also that their _Faces_ differed very much from one another; the _first_ exhibiting all along a matter, which as to its density and rarity, altered from day to day exceedingly, whereas the _second_ retained (to the Authors admiration, who affirms, never to have observed the like) all the time he saw it, one and the same round, dense and bright Speck or Kernel.

All which he concludes 1, With an Intimation of his sense concerning two other Comets, pretended to have been lately seen, _One_ at _Rome_, about the {303} _Girdle of Andromeda_, in the Months of _February_ and _March_, 1664. the other in _Germany_ in _Capricorne_, about _Saturne_ in the head of _Sagittary_, during the Months of _September_ and _October_, 1665. 2ly, With an Advertis.e.m.e.nt of what he has done in that important Work for the Advancement of _Astronomy_, the due _Rest.i.tution of the Fixt Stars, vid._ That he has almost finish't it; himself alone, without trusting to any other mans labour, that was not directed by him.

The _Second_ Part of this Book (the _Mantissa_ to the _Prodromus Cometicus_) endeavours to justifie the Authors Observations touching the former Comet, excepted against by M. _Auzout_, in several particulars; as 1. That it had not pa.s.s'd to the _First_, but _Second_ Star in _Aries_, and had mov'd in quite another Line, than He had described. 2. That its _proper motion_ about the end of _January_ and the beginning of _February_, 1665.

had not been rightly a.s.signed. 3. That the _Bignesse_ of its _Diameter_ had not been truly delivered; Nor 4. The _Faces_ of its _Head_ in due manner represented.

To all which the Author endeavors to answer: 1. By delivering all his Observations of that Comet, thereby to shew, what care and diligence he had used, _particularly_ to make out, how great its _Diurnal motion_ had been; in what proportion, and how far, it decreased, and where and in what degree it increased again: Which being, as he conceives, duly and exactly deduced, and demonstrated, he esteems it afterwards to be easie for every one, versed in these matters, certainly to collect and to judge, what way the Comet, after it became invisible to the naked Eye, and could be no longer observed with _s.e.xtants_ and _Quadrants_, had taken, and what Line it had described. 2, By subjecting all those Observations, with great diligence and labour, to a rigid _Calculus_, thereby to obtain, for every day, the _Longitudes_, _Lat.i.tudes_, _Right Ascensions, Declinations_, _Proper motion_, _Angle_ of the _Ecliptick_ and the _aequator_, and the _Nodes_ of that Comet; for the construction of an _Ephemerides_ of its whole Motion.

From all which he pretends to prove, that he has not erred in his Observation of _February_ 18, nor been prepossest by any _Hypothesis_, nor deluded by any _Fixt Star_, as M. _Auzout_ thinketh; but that near the _First Star_ of _Aries_ there _then_ appear'd a _Phaenomenon_, most like to that Comet, that was seen some dayes before, if compared with the Observations make thereof _Febr._ 12, 13, 14. Though he will not hitherto positively determine, whether that _Phaenomenon_, which appear'd to him _February_ 18. was {304} indeed that very Comet, which he saw with his naked Eye, and observed with his Geometrical Instruments, the said 12, 13, and 14. dayes of _February_; or whether it was another, and whether he had lost that Comet, which moved towards the _Second Star_ in _Aries_: but leaves it to the Learned World, and particularly to the _Royal Society_, after they shall have well examined and considered all his Observations, and the _Calculus_ raised therefrom, to judge of this, and the other particulars in controversie.

II. _Isaacus Vossius de NILI et ALIORUM FLUMINUM ORIGINE_. It was _Numb._ 14. of these _Transactions_, that gave an account of the _Cause_ of the _Inundation of the Nile_, as it was rendred by Monsieur _de la Chambre_: _This_ is to give you another, not only of the _Inundation_, but also of the _Origine_ of that, and of _other Rivers_, as it is delivered by Monsieur _Isaac Vossius_, who undertakes in this Book to shew;

1. That those _Subterraneous Channels_, through which several _Philosophers_ teach, that the Sea discharges it self into the Rivers, are not only imaginary, but useless, in regard 'tis impossible for the water to rise from the Subterraneous places up to the Mountains, where commonly the Sources of Rivers are.

2. He explicates, why, if a Pipe be put into a Bason full of Water, the water is seen more raised in the Pipe, than in the Bason, and rises higher according as the Pipe is narrower; On the contrary, if the same Pipe be put into a Bason full of Quicksilver, the Quicksilver stayes lower in the Pipe, than in the Bason. The reason, which he renders hereof, is, That as the Water sticks easily to all it touches, it is sustain'd by the sides of the narrow Pipe wherein it is included: And indeed, if the Pipe be quite drawn out of the Water, the Water doth not all fall out, but so much of it remains, as the sides of the Pipe could sustaine: Whence it is, that the Water which is kept up by the Walls of the Tube, weighing no longer upon that which is in the Bason, is thrust upwards, and keeps it self raised above its Levell; but the Quicksilver not adhering so easily, as Water, to Bodies it touches, is not sustained by the sides of the Tube, and so mounts not above its Levell, but rather descends below it, because the Pipe, which is streight, hinders the endeavor that is in the _Mercury_ to rise to its Level. He adds, that this Observation makes nothing for the Explication of the _Origine of Rivers_; because, though it be true, that the Water {305} by this means rises above its Levell, yet it does never run out at the top of the Pipe. Having said this, he answers to the other Arguments, commonly alledged to maintain this Opinion.

3. He pretends, that all Rivers proceed from a _Colluvies_ or _Rendevous_ of Rain-waters, and that, as the Water, that falls upon _Hills_, gathers more easily together, than that which falls in _Plaines_, therefore it is, that Rivers ordinarily take their Source from _Hills_. Thence also comes it (saies he) that there are more _Rivers_, than _Torrents_, in the _Temperate Zones_; and, on the contrary, more _Torrents_, than _Rivers_, in the _Torrid Zone_: For, as in hot Climats the Mountains are far higher, the Water, that descends from them with impetuosity, runs away in a little while, and formes such Collections of Water, as soon dry up, but in cold Climats, the Waters do not run away but slowly, and are renew'd and recruited by Rain, before they are quite dryed up; because the Hills are there lower, and so the Bed of Rivers hath lesse declivity.

Having thus discoursed of _Rivers_ in _General_, he treats of the _Nile_ in _particular_; and there

1. Observes, That the Order of the Seasons of the Year is quite inverted under the _Torrid Zone_. For, whereas it should be then Summer, when the Sun is near; and Winter, when the Sun is farther off: Under the _Torrid Zone_ 'tis never lesse hot, than when the Sun is nearest; nor more hot, than when the Sun is farthest off: So that to the people that live between the _aequinoctial_ and the _Tropicks_, Summer begins about _Christma.s.s_, and their Winter, about St. _Johns_ day. The reason whereof is, (_saith he_) that when the Sun is directly over their Heads, it raises abundance of vapors, and draws them so high, that they are presently converted into Water by the coldnesse of the Air; whence it comes to pa.s.se, that then it rains continually, which does refresh the Air; but when the Sun is farther off, there falls no more rain, and so the Heat becomes insupportable.

2. He proves by many recent Relations, that the _Sources_ of the _Nile_ are on this side of the _aequinoctial_ in _aethiopia_, of which he gives a very accurate _Mappe_, correcting many faults which _Geographers_ are wont to commit in the Description of the Kingdom of the _Abyssins_, which they believe to be much greater than indeed it is. {306}

3. This supposed, he easily gives an account, why the _Nile_ yearly overflows about the end of _June_: For, as at that time there falls much rain in _aethiopia_, it must needs be, that the _Nile_, whose source is in that Country, should then overflow, when those rains begin, and subside, when they cease.

There are besides, in this Book, two other _Tracts_. In the _first_, M.

_Vossins_ endeavours to maintain the Doctrine, he had deliver'd in his Book _De Lumine_, and to shew, that the _Soul_ of Animals is nothing but _Fire_, that there are no invisible Atoms; nor so much as any Pores, even in the Skin of man. Here he treats also of _Refractions_, and alledges the Examples of several persons, who have then seen the Sun by the means of Refraction, when really He was under the _Horizon_.

In the _second_, He discourses of some points of the _Mechanicks_; and relates among other things, that the _Arrows_ and _battering Rams (Aries)_ of the Antients did as much execution, as our _Muskets_ and _Canons_; and then, that the Vehemence of the percussion depends as much upon the Length of the percutient Body, as upon the velocity of the Motion. He adds, that the Length of a Canon ought not to exceed 13 foot, and that a greater length is not onely useless, but hinders also the effect of the Gun, not because the Bullet is thrown out of the Gun, before all the powder is fired (as some believe;) but because the Bullet is then beaten back into the Gun by the Air, re-entring into it with impetuosity, when the flame is extinct.

III. _LE DISCERNEMENT DU CORPS ET DE L'AME_, par M. _de Cordemoy_.

This _French_ Treatise (but very lately come to the _Publisher's_ hands) examines the different Operations of the Soul and Body, and the Secret of their Union, pretending to discover to every one, what he is, and what is transacting within him. It consists of six Discourses.

[Sidenote: * _It sounds hard, To say, An _extended_ substance is _indivisible_._]

1. In the _first_, the Author examines the Notions, we have in _general_ of _Bodies_ and _Matter_; of _Quant.i.ty_; of _Qualities_; of _Place_; of _Rest_; of _Motion_; of _Vacuity_; of _Forms_: to shew what is to be understood by these Terms, which cause all the perplexity that is in the ordinary _Physicks_. He begins with taking notice, that hitherto _Philosophers_ have had no _distinct_ notions of _Bodies_ and _Matter_, from the want whereof he conceives, that almost all the Errors in Common _Physiology_ have {307} sprung. To rectify which, he defines _Bodies_ to be * _Extended Substances_, and _Matter_ an _Aggregate of Bodies_. Whence he inferrs, that _Bodies_ are Indivisible and _Matter_ divisible; a _Body_ being nothing but _one_ and the _same_ substance, whose different extremities are inseparable, because they are the extremities of one and the same Extension, and, in a word, of one and the same Substance; but _Matter_ being nothing but an a.s.sociation or Collection of Bodies, 'tis evident, (_saith he_) it must be divisible. This doctrine he so much insists upon, that he conceives, Nature cannot subsist, if a Body in the sence he takes it, be divisible; and that _Motion_ and _Rest_ cannot be explicated without it. As for _Quant.i.ty_, he makes that to be nothing but More or Less Bodies; not allowing, that each Body should be a Quant.i.ty, though it be a part of Quant.i.ty; no more than an _Unite_ is a Number, though it make part of a Number: so that _Quant.i.ty_ and _Extension_ are two distinct things with him, the _first_ belonging properly to _Matter_, the last to a _Body_. Touching _Vacuity_, he conceives, that the Bodies, which compose a ma.s.s, are not every where so near one another, as not to leave some interval in several places. Neither does he think it necessary, that those intervals should be fill'd up; nor unconceivable, that there should be no Body between two Bodies; which touch not one another. And when 'tis said, that those intervals cannot be conceived without Extension, and that consequently there are Bodies that replenish them, he frankly p.r.o.nounces that not to be true; and affirms, that though it may be said, that between two Bodies, which touch not one another, other Bodies may be placed of so or so many feet, &c: yet ought it not to be inferred, that therefore they _are_ there, but onely, that they are thus placed, that there _may_ be put between them so many Bodies, as joyned together would compose an Extension of so many feet. So that one conceives onely, that Bodies _may_ be placed there, but not that they _are_ there: and as we can have an _Idea_ of many Bodies, though none of them be in being; so we can conceive, that some Bodies _may_ be put between others, where really there are none. And when 'tis alledged, that if all the Bodies, that fill a vessel full, were destroyed, the sides of the vessel would be closed together; He professes, he understands not that ratiocination, nor can conceive, what one Body does to the subsistence of another, more than to sustain themselves mutually, when they are thrust by the neighbouring ones: and therefore sees not, why the sides of the vessel should close, if nothing did thrust them together; but understands clearly, that two Bodies may well subsist so far from one another, that one might place a great many Bodies between them, or none at all, and yet they neither approach to, not recoil from one another. {308}

2. In the _Second_, he examines the _Changes_, which he knows in Matter, and makes it his business to explicate all those that respect _Quant.i.ty_, _Qualities_ and _Forms_, by _Local Motion_, esteeming that needs no other.

3. In the _third_, he explains the Motion of _Artificial_ Engins, and that of _Natural_ ones, by one and the same Cause; endeavouring among other things to shew, that the Body of an Animal is moved after the same manner with a Watch. That cause of motion he makes the _Materia Subtilis_; and the finer or subtiler that is, the better and fitter he conceives it to be to preserve Motion.

4. In the _Fourth_, he teaches, that though Experience seems to evince, that the Soul moves the Body, and that one Body moves an other; yet there is nothing but G.o.d, that can produce any notion in the World, and all other Agents, which we believe to be the _Cause_ of this or that Motion, are no more but the _Occasion_ thereof. In doing this, he advances certain _Axioms_, and Conclusions, which are in short,

a. The _Axioms_: That no substance has that of it self, which it can loose, without ceasing to be, what it is: That every body may loose of its motion, till it have no more left, without ceasing to be a Body: That we cannot conceive but two sorts of substances, _vid._ a _Spirit_ (or _That which thinketh_) and a _Body_, wherefore they must be considered as the Causes of all, that happens, and what cannot proceed from the one, must necessarily be adscribed to the other: That to _Move_, or to cause motion, is an Action: That an Action cannot be continued but by the Agent, who began it.

b. The _Conclusions_: That no _Body_ hath Motion of it self: That the First Mover of Bodies not a Body: That it cannot be but a _Spirit_, that is the First Mover: That it cannot be but the same Spirit, who has begun to move Bodies, that continues to move.

In the _Fifth_, He treats of the Union of the Body and Soul, and the manner, how they act one upon the other; and esteems it not more difficult to conceive the Action of Spirits upon Bodies, and of Bodies upon Spirits, than to conceive the Action of Bodies upon Bodies: the cause of the great difficulty in understanding the two former, arising (according to him) from thence, that we will conceive the one by the other, not considering, that every thing acting according to its own nature, we shall never know the action of one Agent, if we will examine it by the notions we have of another, that is of a quite differing nature. Here he notes, that the Action of Bodies upon Bodies is not {309} more known to us; than that of Spirits upon Bodies, or of Bodies upon Spirits; and yet most men admire nothing but _this_, believing to know the _other_; whereas he Judges, that all things being well examin'd, the Action of Bodies upon Bodies is no more conceivable, than that of Spirits upon Bodies. Mean while the opinion of the Authour touching this subject, is, That the union of Soul and Body consists onely in this, that certain motions of the Body are followed by certain _Cogitations_ of the Soul, and, on the contrary, that certain Thoughts of the Soul are follow'd by certain _Motions_ of the Body. And, having supposed, that Bodies are said to act upon one another, when they cause some change suitable to Extension; and Spirits to act upon one another, when they cause some change suitable to a Thought; he infers, that when a Body acts upon a Spirit, that cannot be by causing any change of motion, of figure, or parts, as having none of all these; nor when a Spirit acts upon a Body, that cannot be by producing any change of Thought, as having none: But, when this Body, or its motion, or figure, or other thing, depending upon its nature, can be perceived by a Spirit, so as, upon that occasion, this Spirit has thoughts, it had not before, it may be said, that the Body has acted upon this Spirit, for as much as it has caused all the change in it, whereof it was capable according to its nature.

In the _Sixth_, After he hath shew'd, what is to be understood by what we call _Soul_, and by what we call _Body_, he labours to make it out, that we are much more a.s.sured of the Existence of the Soul, than of that of the Body, which he conceives he can prove from hence, that we cannot doubt, that we think, because even doubting is thinking; but one may doubt, whether one has a body, for several reasons, which he alledges, and thinks so cogent, that he concludes, it is not evident to him by the light of reason, that he has a Body. But supposing, there be Bodies, he examines, what are the Operations, that belong to the Soul, and what those, that belong to the Body; and lastly, what those, that result from the Union of both: And then explains, how all those operations are perform'd, and particularly, _Sensation_; where he shews, that the Nerves, holding at one end to the Brain, whereof they are but Allongations, and being at the other end extended to the extremities of the Body; when an Object comes to touch those exterior ends of the Nerves, the interior ones in the Brain are presently shaken; and cause different sensations according to the diversitie of Nerves, and the differing manner, in which they are shaken.

And to shew, that 'tis this shaking, that causes Sensation, he notes, that if any thing shakes the interior parts of the Nerves, though the object be absent, the Soul has presently the same {310} sensations, as it would have, if it were present. As, if one should knock on's head forcibly against a wall, the shaking, which the blow gives to the Brain, moving the interior extremities of the Nerve, which causes the sensation of Light, the Soul has the same sensation, which it would have, if it saw a thousand Candles: On the contrary, if the interior extremities of the nerves are not shaken, though the object be present, it causes no sensation; whence it comes, that if a strong Ligature be made upon the middle of the Arm, and the hand be then p.r.i.c.kt, no pain is felt, because the shaking of the nerves that are p.r.i.c.ked, being stopped by the Ligature, cannot reach to the extremities of the Nerves, that are within the Brain.

_Advertis.e.m.e.nt._

The following _Errata_, left by the _Press_ in _Num._ 16, the _Reader_ is desired thus to correct.

Page 269. lin 27. read, _motion of B above the Center; G. is also_, with a _Semi-colon_ after the word _Center_. p. 274. l. 13, r. _it to do to the_.

p. 277. l. 24. r. _natural days_. p. 281. l. 16. r. _of his_. ib. l. 27. r.

_a notion_. p. 293. l. 4. r. _enough without_. ib. l. 43. r. _to the Sine of_. p. 294. l. 1. r. _to the Sine of_.