Philosophical Transactions of the Royal Society Part 46

16. Whether the Transfusion may be practic'd upon pregnant b.i.t.c.hes, at least at certain times of their gravidation? And what effect it will have upon the Whelps?

_There_ were some other _Quaeries_ proposed by the same _Author_; as, the weighing of the _Emittent_ Animal before the Operation, that (making an abatement for the Effluviums, and for the Excrements, if it voids any) it may appear, how much blood it really loses. To which were annext divers others not so fit to be perused but by _Physitians_, and therefore here omitted.

_A Method for Observing the _Eclipses of the Moon_, free from the Common Inconveniencies, as it was left by the Learned Mr. _Rook_, late _Gresham_-Professor of Geometry._

Eclipses of the Moon are observed for two princ.i.p.al ends; One _Astronomical_, that by comparing Observations with Calculations, the _Theory_ of the _Moons Motion_ may be perfected, and the _Tables_ thereof reformed: the other, _Geographical_, that by comparing among themselves the Observations of the same _Ecliptick Phases_, made in _divers_ places, the _Difference_ of _Meridians_ or _Longitudes_ of those places may be discerned.

The Knowledge of the Eclipse's Quant.i.ty and Duration, the Shadows, Curvity, and Inclination, &c. conduce only to the former of these ends. The exact time of the Beginning, Middle, and End of Eclipses, as also in _Total_ ones, the Beginning and End of _Total_ darkness, is useful for both of them.

But because in Observations made by the _bare_ Eye, these times considerably differ from those with a _Telescope_; and, because the _Beginning_ of Eclipses, and the _End_ of _Total_ darkness, are scarce to be observed exactly, even with Gla.s.ses (none being able clearly to distinguish between the _True_ Shadow and _Penumbra_, unless he hath seen, for some time before, the Line, separating them, pa.s.s along upon the Surface of the Moon;) and lastly, because in small {389} _Partial_ Eclipses, the Beginning and End, and in _Total_ ones of short continuance in the Shadow, the Beginning and End of _Total_ darkness, are unfit for nice Observations, by reason of the slow change of _Apparences_, which the _Oblique_ Motion of the Shadow then causeth. For these reasons I shall propound a _Method_ peculiarly design'd for the Accomplishment of the _Geographical_ end in Observing Lunar Eclipses, free (as far as is possible) from all the mentioned Inconveniences.

For, _First_, It shall not be practicable without a Telescope. _Secondly_, The Observer shall alwayes have opportunity before his princ.i.p.al Observation, to note the Distinction between the _True Shadow_ and the _Penumbra_. And, _Thirdly_, It shall be applicable to those Seasons of the Eclipse, when there is the suddenest Alteration in the _Apparences_.

To satisfie all which intents,

Let there be of the Eminentest _Spots_, dispersed over all Quarters of the Moons Surface, a select number generally agreed on, to be constantly made use of, to this purpose, in all parts of the World. As, for Example, those, which _M. Hevelius_ calleth,

{ Sinai.

{ { aethna. { Besbicus. { Maeotis.

Mons { Insula. { Palus { { Porphyrites. { Creta. { Maraeotis.

{ Lacus Niger Major.

{ Serorum.

Let in each _Eclipse_, not all, but (for instance) three of these _Spots_, which then lie nearest to the _Ecliptick_, be exactly observed, when they are first touch'd by the _True_ Shadow, and again, when they are just compleatly entred into it, and (if you please) also in the _Decrease_ of the Eclipse, when they are first fully clear from the _True_ Shadow: For the accurate determinations of which moments of time (that being in this business of main importance) let there be taken _Alt.i.tudes_ of remarkable _Fixed Stars_ on this {390} side of the _Line_, of such, as lie between the _aequator_ and _Tropick_ of _Cancer_; but _beyond_ the _Line_, of such, as are situate towards the other _Tropick_; and in all places, of such, as at the time of Observation, are about 4. hours distant from the _Meridian_.

_An Account of some Observations, lately made in _Spain_, by His Excellency the _Earl of Sandwich_._

The Right Honourable the _Earl of Sandwich_, as he appears eminent in discharging the Trust, his Majesty hath reposed in him, of Amba.s.sador Extraordinary to the King of _Spain_; so he forgets not in the midst of that Employment, that he is a Member of the _Royal Society_; but does from time to time, when his weighty State-Negotiations do permit, imploy himself in making considerable Observations of divers kinds, both _Astronomical_ and _Physiological_; and communicateth the same to the said _Society_; as for instance, lately, what he has observ'd concerning the _Solar Eclipse_ in _June_ last, the Suns height in the Solstice, and also the Lat.i.tude of _Madrid_, esteeming by the Suns Alt.i.tude in the _Solstice_, and by other Meridian Alt.i.tudes, the _Lat.i.tude_ of _Madrid_ to be 40 deg. 10 min; which differs considerably from that a.s.signed by others; the General Chart of _Europe_ giving to it 41 deg. 30 min. the General Map of _Spain_, 40 deg.

27 min. A large Provincial Map of _Castile_, 40 deg. 38 min.

To these particulars, and others formerly imparted, his Excellency is making more of the same nature; and particularly those of the Immersion of the _Satellites_ of _Jupiter_.

We must not omit mentioning here, what he hath observed of _Halo_'s about the _Moon_; which he relates in these words;

_Decemb._ 25. _Old Style_, 1666. In the Evening, here (vid. at _Madrid_) was a great _Halo_ about the Moon, the _Semidiameter_ whereof was about 23 deg. 30 min. _Aldebaran_ was just in the _North-east_ part of the _Circle_, and the two Horns of _Aries_ just enclosed by the _South-west_ of the _Circle_, the Moon being in the _Center_. I note this the rather (_saith he_) because five or six years ago, vid. _Novemb._ 21. _Old Style_, 1661.

an hour after Sun-set, I saw a great _Halo_ about the Moon of the same _Semidiameter_, {391} at _Tangier_, the Moon being very near the same place, where she was now.

_Extract of a Letter, lately written by Mr. _Nathaniel Fairfax_ to the _Publisher_, containing Observations about some _Insects_, and their Inoxiousness, &c._

The Ingenious Author of this Letter, as he expresses an extraordinary desire to see the _Store-house_ of _Natural Philosophy_, more richly fraughted (a Work begun by the single care and conduct of the Excellent Lord _Verulam_, and prosecuted by the Joynt-undertakings of the _R.

Society_) so he very frankly offers his Service in contributing some of his Observations, and begins in this very Letter to perform his Offer. For, Having taken notice of what was publisht in _Numb. 9. p. 161_. out of the _Italian_ Philosopher _Redi_, vid. That Creatures, reputed Venomous, are indeed no Poysons, when swallow'd, though they may prove so, when put into Wounds: He, for confirmation thereof, alledges Examples of several Persons well known to him (himself also having been an Eye-witness to some such Experiments) who have frequently swallow'd _Spiders_, even of the rankest kind, without any more harm than happens to Hens, Robin-red-b.r.e.a.s.t.s, and other Birds, who make Spiders their daily Commons. And having made mention of some men, that eat even _Toads_, he adds, that though a Toad be not a Poyson to us in the whole; yet it may invenome outwardly, according to some parts so and so stirr'd; an instance whereof he alledges in a Boy, who stumbling on a Toad, and hurling stones at it, some Juyce from the bruised Toad chanced to light upon his Lips, whereupon they swell'd, each to the thickness of about two Thumbs: And he neglecting to use, what might be proper to restore them, they have continued in that mishapen size ever since; the ugliness whereof, when the Relator saw, gave him occasion to inquire after the cause of it, which thereupon he understood to be, as has been recited.

On this occasion, the same Gentleman relates, that once seeing a Spider bruised into a small Gla.s.s of Water, and that it tinged {392} it somewhat of a Sky-colour, he was, upon owning his surprise thereat, informed, that a dozen of them being put in, they would dye it to almost a full _Azure_.

Which is touch't here, that, the Experiment being so easie to make, it may be tried, when the season furnishes those Insects; meantime, it seems not more incredible, that this Creature should yield a Sky-colour, when put in water, than that _Cochineel_, which also is but an Insect, should afford a fine _red_, when steep'd in the same Liquor.

_An Account Of Some Books._

_I._ Le Tome troisieme et dernier des Lettres de _M. DES-CARTES_.

As the two first _Tomes_ of M. _Des-Cartes_ his Letters, contain Questions, for the most part of a _Moral_ and _Physiological_ Nature, proposed to, and answer'd by him; so _this_ consists of the Contests, he had upon several Subjects with divers Men eminent in his time.

To pa.s.s by that sharp Contest, he was engaged in by some Professors of Divinity at _Utrecht_, who endeavoured to discredit his Philosophy, as leading to Libertinisme and Atheisme, notwithstanding he made it so much his business, as to a.s.sert the Existence of a Deity, and the Immortality of a Soul: We shall take notice of what is more to our purpose, _vid._ the Differences, he had touching his _Dioptricks_ and _Geometry_.

As for his _Dioptricks_, though a great part of the Learned World have much esteem'd that Treatise, as leaving little to be said after him upon that Subject; yet there have not been wanting Mathematicians, who have declared their disagreement from his Principles in that Doctrine. The first of them was the Jesuit _Bourdin_, Mathematick Professor in the Colledg of _Clermont_ at _Paris_; but this difference was soon at an end. A second was Mr. _Hobbs_, upon whose account he wrote several Letters to _Mersennus_, containing many remarks conducing to the Knowledge of the Nature of _Reflection_ and _Refraction_. But the Person, that did most learnedly and resolutely attack the said _Dioptricks_, was Monsieur _Fermat_, {393} writing first about it to _Mersennus_, who soon communicated his Objections to M. _Des-Cartes_, who failed not to return his Answer to them. But _Fermat_ replied, and _Des-Cartes_ likewise; and after many reciprocations, in which each party pretended to have the advantage, the matter rested; until M. _Fermat_ taking occasion to write afresh of it to M. _De la Chambre_, several years after _Des-Cartes_'s death, upon occasion of a Book, written M. _De la Chambre_, _Of Light_; discoursed with this new _Author_ after the same rate, as he had done before with _Des-Cartes_ himself, and seemed to invite some-body of his friends, to re-a.s.sume the former contest. Whereupon M. _Clerselier_ and M. _Rohault_ took up the Gantlet, to a.s.sert the Doctrine of the deceased Philosopher, exchanging several Letters with M. _Fermat_, all inserted in this _Tome_, and serving fully to instruct the Reader of this Difference, and withal to elucidate many difficult points of the Subject of _Refractions_; especially of this particular, _Whether the Motion of Light is more easily, and with more expedition, perform'd through _dense_ Mediums, than _rare_._

Besides this, though one would think, Disputes had no place in _Geometry_, since all proofs there, are as many Demonstrations; yet M. _Des-Cartes_ hath had several scufles touching that Science. As M. _Fermat_ had a.s.saulted his _Dioptricks_, so He reciprocally examined his Treatise _De Maximis & Minimis_, pretending to have met with _Paralogismes_ in it. But the Cause of M. _Fermat_ was learnedly pleaded for, by some of his Friends, who took their turn to examine the Treatise of _Des-Carte_'s Geometry; whereupon many _Letters_ were exchanged, to be found this Book, and deserving to be considered; which doubtless the Curious would easily be induced to do, if Copies of this Book were to be obtain'd here in _England_, besides that one, which the _Publisher_ received from his _Parisian_ Correspondent, and which affords him the opportunity of giving this, though but Cursory, Account of it.

As to _Physicks_, there occur chiefly two Questions, learnedly treated of in this _Volume_, though not without some heat between M. _Des-Cartes_ and M. _Roberval_. The _one_ is, touching the Vibrations of Bodies suspended in the Air, and their Center of Agitation: about which, there is also a Letter inserted of {394} M. _Des-Cartes_ to that late n.o.ble and Learned English Knight, Sir _Charles Cavendish_. The _other_ is, whether Motion can be made without supposing a _Vacuum_: where 'tis represented, That, if one comprehend well the Nature, ascribed to the _Materia subtilis_, and how Motions, called _Circular_, are made, which need not be just _Ovals_ or _true_ Circles, but are only called Circular, in regard that their Motion ends, where it had begun, whatever irregularity there be in the Middle; and also, that all the Inequalities, that may be in the Magnitude or Figure of the parts, may be compensated by other inequalities, met with in their Swiftness, and by the facility, with which the parts of the _Subtle Matter_, or of the first _Cartesian_ Element, which are found every where, happen to be divided, or to accommodate their Figure to the s.p.a.ce, they are to fill up: If these things be well understood and considered, that then no difficulty can remain touching the Motion of the parts of Matter _in pleno_.

Besides all these particulars, treated of in this _Tome_, there occur many pretty Questions concerning _Numbers_, the _Cycloid_, the manner of _Working Gla.s.ses for Telescopes_, the way of _Weighing Air_, and many other Curiosities, Mathematical and Physical.

_II. _ASTRONOMIA REFORMATA_, Auctore _JOHANNE BAPT. RICCIOLI_, Soc. Jesu._

For the Notice of this Book, and the Account of the Chief Heads contained therein, we are obliged to the _Journal des Scavans_; which informs us,

_First_, That the Design of this Work is, that, because several _Astronomers_, having had their several _Hypotheses_, there is found so great a diversity of opinions, that it is difficult thence to conclude any thing certain; this Author judged it also necessary, to compare together all the best Observations, and upon examination of what they have most certain in them, to reform upon that measure the Principles of Astronomy.

_Secondly_, That this _Volume_ is divided into two Parts, whereof the _First_ is composed of _Ten_ Books; in which the Author {395} considers the princ.i.p.al Observations, hitherto made of the Motion of the Planets and the Fixed Stars, of their Magnitude, Figure, and other Accidents; drawing thence several Conclusions, in which he establishes his _Hypothesis_. The _second_ contains his _Astronomical Tables_, made according to the _Hypotheses_ of the First Part, together with Instructions teaching the manner of using them.

_Thirdly_, That Astronomers will find in this Book many very remarkable things, concerning the _Apparent Diameter of the Sun_ and the other Stars, the Motion of the _Libration of the Moon_, the _Eclipses_, _Parallaxes_, and _Refractions_: And that this Author shews, that there is a great difference between _Optical_ and _Astronomical_ Refraction, which _Tycho_ and many others have confounded; undertaking to prove, that, whereas these _Astronomers_ have believed, that the remoter any Star is, the less is its Refraction, on the contrary the Refraction is the greater, the more a Star is distant. And among many other things, he ingeniously explicates the two contrary Motions of the Sun, from East to West, and _vice versa_, by one onely Motion upon a _Spiral_, turning about a _Cone_.

_Fourthly_, That he represents, How uneasie it is to establish sure Principles of this Science, by reason of the difficulties of making exact Observations. So, for example, in the Observation of the _Equinox_, every one is mistaken by so many _Hours_, as he is of _Minutes_, in the Elevation of the _Pole_, or the Diameter of the Sun, or the Refraction, or in any other circ.u.mstance. In the Observation of the _Solstice_, the error of one only _Second_ causeth a mistake of an _Hour_ and an _half_: mean time 'tis almost impossible to avoid the error of a _Second_; and even the sharpest sight will not be able to perceive it, except it be a.s.sisted with an Instrument of a prodigious bigness. For to mark _Seconds_, though Lines were drawn as subtil as the single threds of a Silk-worms Clew, (which are the smallest s.p.a.ces to be discerned by the sharpest Eye) by the Calculation made by this Author there would need an Instrument of 48. feet _Radius_, since Experience shews, that there needs no more at most, than 3600. threds of Silk to cover the s.p.a.ce of an _inch_. But, suppose one could have a _Quadrant_ of this bigness, who can a.s.sure himself, that dividing it into {396} 324000. parts (for so many _Seconds_ there are in 90. _Degrees_) either in placing it, or in observing, he shall not mistake the thickness of a single thred of Silk? He adds, that Great Instruments have their defects, as the small ones: For in those, that are _Movable_, if the thred, on which the Lead hangs, is any thing big, it cannot exactly mark _Seconds_; if it be very fine, it breaks, because of its great length, and the weight of the Lead: And in the _Fixed_ ones, the greater the _Diameter_ is, the less the Shadow or the Light is terminated; so that it is painful enough, exactly to discern the extremities thereof. Yet 'tis certain, that the greater the Instruments are, the surer _Astronomers_ may be: Whence it is, the some _Astronomers_ have made use of _Obelisks_ of a vast bigness, to take the _Alt.i.tudes_; and Signior _Ca.s.sini_, after the example of _Egnatio Dante_, caused a hole to be made on the highest part of a Wall of 95. feet in a Church at _Bononia_, through which the beams of the Sun falling on the Floor, mark as exactly as is possible, the height of that Luminary.

_Fifthly_, That the Author reasons for the _Immobility of the Earth_ after this manner. He supposes for certain, that the swiftness of the Motion of heavy bodies doth still _increase_ in their descent; to confirm which principle, he affirms to have experimented, That, if you let fall a Ball into one of the Scales of a Ballance, according to the proportion of the height, it falls from, it raiseth different weights in the other Scale. For example, A Wooden Ball, of 1 ounce, falling from a height of 35 inches, raiseth a weight of 5. ounces; from the height of 140 inches, a weight of 20 ounces; from that of 315 inches, one of 45 ounces; and from another of 560 inches, one of 80 ounces, &c. From this principle he concludes the Earth to be at Rest; for _saith he_, if it should have a Diurnal Motion upon its Center, Heavy Bodies being carried along with it by its motion, would in descending describe a _Curve Line_, and, as he shews by a _Calculus_, made by him, run equal s.p.a.ces in equal times; whence it follows, that the Celerity of their Motion would not increase in descending, and that consequently their stroke would not be stronger, after they had fallen thorow a longer s.p.a.ce. {397}

_III. _ANATOME MEDULLAE SPINALIS, ET NERVORUM_ inde provenientium, _GERARDI BLASII_, M. D._

The Author shews in this little _Tract_ a way of taking the entire _Medulla Spinalis_, or Marrow of the Back, out of its _Theca_ or Bony Receptacle _without Laceration_; which else happens frequently, both of the Nerves proceeding from it, and of the Coats investing it; not to name other parts of the same. This he affirms to have been put into practice by himself, by a fine Saw and Wedge; which are to be dexterously used: and he produceth accordingly in excellent Cuts, the Representations of the Structure of the said _Medulla_ thus taken out, and the _Nerves_, thence proceeding; and that of several Animals, Dogs, Swine, Sheep.

He intermixes several Observations, touching the _Singleness_ of this _Medulla_, against _Linda.n.u.s_ and others; its _Original_; vid. Whether it be the Root of the Brain, or the Brain the Root of it: its difference of _Softness_ and _Hardness_ in several Animals; where he notes, that in _Swine_ it is much softer than in Dogs, &c.

He exhibits also the Arteries, Nerves, and Veins, dispersed through this _Medulla_, and inquires, Whether the _Nerves_ proceed from the _Medulla_ it self, or its _Meninx_; and discourses also of the _Principle_ and _Distribution_ of the Nerves; referring for ampler information in this and the other particulars, to that Excellent Book of the Learned Dr. _Willis_, _De Anatome Cerebri_. {398}