Philosophical Transactions of the Royal Society Part 15

The other usual way both in _Italy_ and other Countries, to conserve Snow and Ice with _Straw_ or _Reed_, is set down so punctually by Mr. _Boyle_ in his _Experimental History of Cold_, pag. 408. 409. that nothing is to be added. It seems _Pliny_ could not pa.s.s by these _Conservatories_, and the cooling of drinks with Ice, without pa.s.sing this severe, though elegant and witty, Animadversion upon them: _Hi Nives, illi glaciem potant, poenasque montium in voluptatem gulae vertunt: Servatur algor aestibus, excogitaturque ut alienis mensibus nix algeat_, lib. 19. cap. 4. But the _Epigrammatist_ sports with it thus;

_Non potare nivem, sed aquam potare rigentem_ _De nive, commenta est ingeniosa sitis._ Martial. 14. _Ep._ 117.

_Directions for Sea-men, bound for far Voyages._

It being the Design of the _R. Society_, for the better attaining the End of their Inst.i.tution, to study _Nature_ rather than _Books_, and from the Observations, made of the _Phaenomena_ and Effects she presents, to compose such a {141} History of Her, as may hereafter serve to build a Solid and Useful Philosophy upon; They have from time to time given order to several of their Members to draw up both _Inquiries_ of things Observable in forrain Countries, and _Directions_ for the Particulars, they desire chiefly to be informed about. And considering with themselves, how much they may increase their _Philosophical_ stock by the advantage, which _England_ injoyes of making Voyages into all parts of the World, they formerly appointed that Eminent Mathematician and Philosopher Master _Rooke_, one of their Fellowes, and _Geometry_ Professor of _Gresham Colledge_ (now deceased to the great detriment of the Common-wealth of Learning) to think upon and set down some _Directions_ for _Sea-men_ going into the _East_ & _West-Indies_, the better to capacitate them for making such observations abroad, as may be pertinent and suitable for their purpose; of which the said Sea-men should be desired to keep an exact _Diary_, delivering at their return a fair Copy thereof to the _Lord High Admiral_ of _England_, his Royal Highness the _Duke_ of _York_, and another to _Trinity-house_ to be perused by the _R. Society_. Which _Catalogue_ of _Directions_ having been drawn up accordingly by the said Mr. _Rook_, and by him presented to those, who appointed him to expedite such an one, it was thought not to be unseasonable at this time to make it publique, the more conveniently to furnish Navigators with Copies thereof. They are such, as follow;

1. To observe the Declination of the _Compa.s.s_, or its Variation from the _Meridian_ of the place, frequently; marking withal, the _Lat.i.tude_ and _Longitude_ of the place, wherever such Observation is made, as exactly as may be, and setting down the _Method_, by which they made them.

2. To carry _Dipping Needles_ with them, and observe the Inclination of the Needle in like manner.

3. To remark carefully the Ebbings and Flowings of the Sea, in as many places as they can, together with all the Accidents, {142} Ordinary and Extraordinary, of the Tides; as, their precise time of Ebbing and Flowing in Rivers, at _Promontories_ or _Capes_; which way their Current runs, what Perpendicular distance there is between the highest Tide and lowest Ebb, during the Spring-Tides and Neap-Tides; what day of the _Moons_ age, and at times of the year, the highest and lowest Tides fall out: And all other considerable Accidents, they can observe in the Tides, cheifly neer Ports, and about Ilands, as in St. _Helena_'s Iland, and the three Rivers there, at the _Bermodas_ &c.

4. To make Plotts and Draughts of prospect of Coasts, Promontories, Islands and Ports, marking the Bearings and Distances, as neer as they can.

5. To sound and marke the Depths of Coasts and Ports, and such other places nere the sh.o.a.r, as they shall think fit.

6. To take notice of the Nature of the Ground at the bottom of the Sea, in all Soundings, whether it be Clay, Sand, Rock, &c.

7. To keep a Register of all changes of Wind and Weather at all houres, by night and by day, shewing the point the Wind blows from, whether strong or weak: The Rains, Hail, Snow and the like, the precise times of their beginnings and continuance, especiall _Hurricans_ and _Spouts_; but above all to take exact care to observe the _Trade-Winds_, about what degree of _Lat.i.tude_ and _Longitude_ they first begin, _where_ and _when_ they cease, or change, or grow stronger or weaker, and how much; as near and exact as may be.

8. To observe and record all Extraordinary _Meteors_, Lightnings, Thunders, _Ignes fatui_, Comets, &c. marking still the places and times of their appearing, continuance. &c.

9. To carry with them good Scales, and Gla.s.se-Violls of a pint or so, with very narrow mouths, which are to be fill'd with Sea-water in different degrees of _Lat.i.tude_, as often as {143} they please, and the weight of the Vial full of water taken exactly at every time, and recorded, marking withall the degree of _Lat.i.tude_, and the day of the Month: And that as well of water near the Top; as at a greater Depth.

_Some Observations concerning _Jupiter_. Of the shadow of one of his _Satellites_ seen, by a Telescope pa.s.sing over the Body of _Jupiter_._

I have received an Account from very good hands, That on the 26^{th.} of _September_ last, at half hour after seven of the Clock, was seen, both in _Holland_ and in _France_ (by curious Observers, with very good Telescopes) the shadow of one of the _Satellites_ of _Jupiter_, pa.s.sing over his Body.

One of those small Stars moving about his Body (which are therefore called his _Satellites_) coming between the Sun and it, made a small Eclipse, appearing in the Face of _Jupiter_ as a little round black Spot. The Particulars of those Observations, when they shall come to our Hands, we may (if need be) make them publik: Which Observations, as they are in themselves very remarkable, and argue the Excellency of the Gla.s.ses by which they were discovered; So are we, in part, beholding to Monsieur _Ca.s.sini_ for them, who giving notice before hand of such Appearances to be expected, gave occasion to those Curious Observers to look for them.

_Of a permanent Spot in _Jupiter_: by which is manifested the conversion of _Jupiter_ about his own Axis._

Besides that Transient Shadow last mentioned, there hath been observed, by Monsieur _Ca.s.sini_, a permanent Spot in the Disque of _Jupiter_; by the help whereof, he hath been able to observe, not onely that _Jupiter_ turns about upon his own Axis, but also the Time of such conversion; which he {144} estimates to be, 9 hours and 56 minutes.

For as _Kepler_ did before conjecture, from the motion of the Primitive Planets about the Sun as their Center, that the Sun moved about its own Axis, but could not prove it, till by _Galileo_ and _s.h.i.+ner_ the Spots in the Sun were discovered; so it hath been thought reasonable, from the Secundary Planets moving about _Jupiter_, that _Jupiter_ is also moved about his Axis; yet, till now, it hath not been evinced by Observation, That it doth so move; much less, in what Period of Time. And the like reason there is to judge so of _Saturn_, because of the Secundary Planet discovered by Monsieur _Hugens de Zulichem_ to move about it; (though such motion be not yet evinced from Observation:) as well as that of the _Earth_, from its Attendant the _Moon_.

Whether the same may be also concluded of the other Planets, _Mars_, _Venus_, and _Mercury_, (about whom have not yet been observed any Secondary Planets to move,) is not so evident. Yet there may be somewhat of like probability in those. Not onely, because it is possible they may have Secundary Planets about them, though not yet discovered; (For, we know, it was long after those of _Jupiter_, before that about _Saturn_ was discovered; and who knows, what after times may discover about the rest?) But because the Primary Planets being all in like manner inlightned by the Sun, and (in all likely hood) moved by it; it is likely that they be moved by the same Laws and Methods; and therefore, turn'd about their own Axis, as it is manifest that some of them are.

But, as for the Secundary Planets, as well those about _Jupiter_, as that about _Saturn_; it is most likely that they have no such Rotation upon their Axis. Not so much because, by reason of their smalness, no such thing hath been yet observed, (or, indeed, could be, though it were true;) But because they being a.n.a.logical to our _Moon_, it is most likely that they are moved in like manner. Now, though it be {145} true, that there is some kind of _Libration_ of the Moon's body, so that we have not precisely just the same part of it looking towards us; (as is evident by _Hevelius_ observations, and others;) yet is there no Revolution upon its Axis; the same part of it, with very little alteration, always respecting us, as is to be seen in _Hevelius_ his Tratise _de Motu Lunae Libratorio_, and indeed, by all those who have written particularly of the spots on the Moon; and is universally known to all that have with any curiosity viewed it with Telescopes.

_Of some Philosophical and curious Books, that are shortly to come abroad._

1. Of the _Origine_ of _Forms_ and _Qualities_, deduced from _Mechanical_ Principles; by the Honorable _Robert Boyle_ Esq.

2. _Hydrostatical Paradoxes_, by the same. Both in _English_.

3. A Tract of the _Origine_ of the _Nile_, by Monsieur _Isaac Vossius_, opposed to that of Monsieur _de la Chambre_, who is maintaining, That _Niter_ is the princ.i.p.al cause of the Inundation of that River.

4. A Dissertation of _Vipers_, by _Signor Redi_, an _Italian_.

5. A Discourse of the _Anatomy_ of _a Lyon_, by the same.

6. Another, _De Figuris Salium_, by the same.

7. A Narration of the Establishment of the _Lyncei_, an _Italian_ Academy, and of their Design and Statutes: the Prince _Cesi_ being the Head of them, who did also intend to establish such Philosophical Societies in all parts of the World, and particularly in _Africa_ and _America_, to be by that means well informed of what considerable productions of Nature were to be found in those parts. The Author yet _Anonymus_.

8. To these I shall add, a Book newly Printed in _Oxford_ (and not yet dispersed) being, _A Catalogue of Fixed Stars_ with their _Longitudes, Lat.i.tudes, and Magnitudes_, according to the _Observations_ of _Uleg-Beig_ (a King, and famous Astronomer, who was _Great-Grand-childe_ to the famous {146} _Tamerlane_, and one of his Successors in some of his Kingdoms) made at _Samarcand_, his cheief seat, (for the year of the Hegira 841, for the year of Christ 1427), who not finding the _Tables_ of _Ptolemy_ to agree sufficiently with the Heavens, did with great diligence, and expense, make observations anew; as _Tycho Brahe_ hath since done. It is a small part of a larger _Astronomical Treatise_ of his, whereof there be divers _Persian_ Ma.n.u.script Copies in _Oxford_. Out of which this is Translated and Published, both in _Persian_ and _Latine_, by Mr. _Thomas Hyde_, now Library Keeper to the _Bodleyan_ Library in _Oxford_: (with Commentaries of his annexed:) Like as another part of it hath formerly been by Mr. _John Graves_. And it were a desirable work that the whole were Translated, that we might be the better acquainted with what was the Eastern Astronomy at that time.

_Published with License._

Oxford, Printed by _A: & L: Lichfield_, for _Ric: Davis_. 1666.

{147}

_Num._ 9.

PHILOSOPHICAL _TRANSACTIONS._

_Munday_, _Feb._ 12. 1665/6.

The Contents.

_An _Apendix_ to the _Directions_ for Seamen, bound for far voyages. Of the judgment of some of the _English_ Astronomers, touching the difference between two learned men, about an Observation made of the first of the two late _Comets_. Of a _Correspondency_, to be procured, for the finding out of the _True_ distance of the _Sun_ and _Moon_ from the Earth. Of an Observation not long since made in _England_ of _Saturn_. An Account of some _Mercurial_ Observations, made with a _Barometer_, and their Results. Some Observations of _Vipers_, made by an _Italian_ Philosopher._

_An _Appendix_ to the _Directions_ for Seamen, bound for far Voyages._