The Motion of the Late Comet Praedicted

The Third, respects Jupiter, wherein Campani affirms he hath observed by the goodness of his Glasses, certain protuberancies and inequalities, much greater than those that have been seen therein hitherto. He addeth, that he is now observing, whether those fallies in the said Planet do not change their situation, which if they should be found to do, he judgeth, that Jupiter might then be said to turn upon his Axes; which, in his opinion, would serve much to confirm the opinion of Copernicus. Besides this, he affirms, he hath remarked in the Belts of Jupiter, the shadows of his satellites, and followed them, and at length seen them emerge out of his Disk. A Spot in one of the Belts of Jupiter. The Ingenious Mr. Hook did, some months since, intimate to a friend of his, that he had, with an excellent twelve foot Telescope, observed, some days before, he than spoke of it, (videl. on the ninth of May, 1664. about 9 of the clock at night) a small Spot in the biggest of the 3 obscurest Belts of Jupiter, and that, observing it from time to time, he found, that within 2 hours after, the said Spot had moved from East to West, about half the length of the Diameter of Jupiter. The Motion of the late Comet predicted. There was lately sent to one of the Secretaries of the Royal Society a Packet, containing some Copies of a Printed Paper, Entituled, The Ephemerides of the Comet, made by the same Person, that sent it, called Monsieur Auxout, a French Gentleman of no ordinary Merit and Learning, who desired, that a couple of them might be recommended to the said Society, and one to their President, and another to his Highness Prince Rupert, and the rest to some other Persons, nominated by him in a Letter that accompanied this present, and known abroad for their singular abilities and knowledge in Philosophical Matters. The end of the Communication of this Paper was, That, the motion of the Comet, that hath lately appeared, having been predicted by the said Monsieur Aux- tout, after he had seen it (as himself affirms) but 4 or 5 times: the Virtuosi of England, among others, might compare also their Observations with his Ephemerides; either to confirm the Hypothesis, upon which the Author had before hand calculated the way of this Star, or to undeceive him, if he be in a mistake. The said Author Dedicateth these his conceptions to the most Christian King, telling him, that he presents Him with a design, which never yet was undertaken by any Astronomer, all the World having been hitherto perswaded, that the motions of Comets were so irregular, that they could not be reduced to any Laws, and men having contented themselves, to observe exactly the places, through which they did pass; but no man, that he knows, having been so bold as to venture to foretel the places, through which they should pass, and where they should cease to appear: Whereas he exhibites here the Ephemerides, determining day by day, in what place of the Heavens this Comet shall be, at what hour it shall be in its Meridian, and at what hour it shall set; until its too great remoteness, or the approach of the Sun, hide it from our eyes. Descending to particulars, he saith, that this Star, being disengaged from the beams of the Sun might have been observed, if his conjectures be good, ever since it hath been of 17 or 18 degrees Southern Latitude, and that about the middle of November last, and sooner, unless it have been too small: That however it hath been seen in Holland ever since the 2d. of December last, at which time, according to his reckoning, the Diurnal motion of the Comet should already amount to 17 or 18 minutes. He finds, that this Star moveth just enough in the Plan of a Great Circle, which inclineth to the Equinoctial about 30 degrees, and to the Ecliptick about 49d. or 45½ cutting the Equator at about 45d ½, and the Ecliptick at the 28d. of Aries, or a little more. He faith just enough, because he thinks, there may perhaps be some parallaxe, which he wisheth could be determined. Hence, (so he goes on) every one who pleaseth, may see, in tracing the Comet upon the Globe, through, or by which Stars it hath passed, and shall pass; adding, that there will be neither cause to wonder, that having descended to about 6 deg. beneath the Tropick of Capricorn, he hath remounted afterwards, and shall go on on ascending so, as to pass the Equinoctial, and perhaps proceed to 15° degrees Northern Declination, if it do not disappear before that time, by reason of its remoteness: Nor to believe, that there have been two Comets, upon its being seen again the 31st of December; since, according to him, it ought to have been so, if it continue to move in a Great Circle. Having hereupon shewed, how the motion is to be traced upon the Globe, he finds, that, according to his Calculation, this Comet was to pass the Tropick of Capricorn about the 16th of December, and being entered into the Sign of Virgo on the 20th of the same month, and having been in Quadrat with the Sun, it should still descend, until the 26th of December in the morning, and then enter into Leo; that having entered, the 28th of the same month, into Cancer, and been, a little after that time, in its greatest Inclination to the Ecliptick, vid. in the 28th degree of Leo, it was to repass the Southern Tropick, over against the little Dogg, on the 29th of December about 9 or 10 of the clock in the morning; after it had been opposite to the Sun 2 or 3 hours before; and that on the 29th of December in the evening it should be in Gemini; and at the very beginning of the New year, enter into Taurus. After this, our Author finds, that this Comet, according to his account, should pass the Equator, on the 4th of January before noon, and that about 5 or 6 of the clock in the evening of that day it was to come into the jaw of the Whale, and the 9th of the same, at 6 of the clock, it should come close to the small Star of the Whale, which is in its way, a little below. At length he finds that it was to enter into Aries on the 12th of January, and to cut the Ecliptick on the 16th of the same month about noon, at which time it was to be again in Quadrat with the Sun, whence drawing a little to above the Northern Line of Pisces, it should in his opinion cease to appear a little beyond that place, without going as far as to the middle of Aries, if so be that its remoteness make it not disappear sooner. He continueth, and saith, that this Comet shall not arrive to the place over against the Line of Pisces till the 10th of February, &c. that then its Diurnal motion shall not exceed 8 minutes, and not 5 minutes about the 20th of the same month: and that in the beginning... ginning of March, if we see it so long, the said motion shall not exceed 4 minutes, and so shall be still diminishing; except the Comet become Retrograde, which, as very important, he would have well observed; as also, whether its motion will be about the end more or less swift, than he hath calculated it. He subjoyneth, that the greatest way, which this Star could make in 24 hours, hath been 13. d. 25'; and in one hour, about 34's and, thinking it probable, that about the time, when it made so much way, it should be nearest to the Earth, he concludeth that its motion in 24 hours must be, in its least distance from the Earth, as about 3. to 14, or 1. to 4½, and that its motion in one hour was to be to the same least distance, as about 1. to 102½. But that, which he judgeth most remarkable, is, that he found by his Calculation, that the said least distance should be on the 29. of December, when the Comet was opposite to the Sun; which he does not know whether it may not serve to decide the grand Question concerning the Motion of the Earth. He taketh further notice, that the Tail of the Comet was to turn Westward, with a point to the North, until the 29. of December, at which time it was to be opposite to the Sun, and that then the said Tail was to look directly North; but that, after that time, the Tail was to turn Eastward, and continue to do so, until it disappear; and that it shall draw a little towards the North, until the 8. or 10. of February, at which time the Tail is to be parallel to the Equator, as if the Comet be yet seen for some time after, the Tail shall go a little lower towards the South, but grow smaller. He finds by his Hypothesis, that on the 2. of December, which is the first observation, that he hath heard of, this Star was to be about 7 times more remote from the Earth, than when it was in its Perigeeum; and that it will be again in an equall remoteness from the Earth, on the 27. of January, so that he is of opinion, that in case this Comet have not been seen before the 2. of December, it will not be seen any more after the 27. of January. He wishes above all things, that it might be very exactly observed, at what Angle the way of the Comet cuts the Equator, and, most of all, the Ecliptick, that so it may be seen, whether there there hath not been some Parallaxe in the Circle of his Motion; also, that some observations could be had of its greatest descent beneath the Tropick of Capricorn in the more Southern parts, where he faith it would have been without Refractions; Moreover of the Time, when it hath been in Quadrat with the Sun about the 20 of December; and that also very exact Observation might be made of the time of its being again in Quadrat with the Sun, which, according to him, was to be January 16. He wishes also, that some in Madagascar may have observed this Star; Seeing that it began to appear over the middle of that Island, and passed twice over their heads; he judgeth, that they have seen it before us. And he wisheth lastly, that there were some intelligent person in Guiana to observe it there, seeing that within a few daies, according to his reckoning, it will pass over their Heads, and will not remove from thence but 8 or 10 degrees Northward, where he saith, it will disappear; thinking it improbable, that it can still appear, after the Sun shall have passed it. This Account beareth date of the 2. January, new stile, 1665, and the Author thereof addeth this Note, That, seeing it could not be printed nor distributed so soon as he desired, he hath had the opportunity to verify it by some Observations, from which he affirms he hath found no sensible difference; or, if there be, that it proceeds only from thence, that the Stars have advanced, since his Globe was made. He concludeth, that if this continue, and the first Observations do likewise agree, or that the differences do arrive within the Times, guessed by him, that he hopes, he shall determine both the Distance and the Magnitude of this Comet; and that perhaps one may be enabled to decide the Question of the Motion of the Earth. In the interim, he assureth, that he hath not changed the least number in his Calculations, and that Monsieur Huygens, and several French Gentlemen, to whom he saith, he hath given them long since, can bear him witness that he hath done so; as also many other friends of his, who saw upon his Globe, several daies before, the way of the Comet from day to day. Thus for the Parisian Account of the Comet, which is here inserted at large, that the intelligent and curious in England may compare compare their Observations therewith, either to verify these Predictions, or to shew wherein they differ; which is (as was also hinted above) the design of this Philosophical Prophet in dispersing his Conceptions, who declareth himself ready, in case he be mistaken in his reckoning, to learn another Hypothesis, to explicate these admirable appearances by. An Experimental History of Cold. There is in the Press, a New Treatise, entitled, New Observations and Experiments in order to an Experimental History of Cold, begun by that Noble Philosopher, Mr. Robert Boyle, and in great part already Printed; He did lately very obligingly present several Copies of so much as was Printed, to the Royal Society, with a desire that some of the Members thereof might be engaged to peruse the Book, and select out of it for trial, the hints of such Experiments, as the Author there wisheth might be either yet made or prosecuted. The Heads thereof are, 1. Experiments touching Bodies capable of Freezing others. 2. Experiments and Observations touching Bodies Disposed to be Frozen. 3. Experiments touching Bodies, Indisposed to be Frozen. 4. Experiments and Observations touching the Degrees of Cold in several Bodies. 5. Experiments touching the Tendency of Cold Upwards or Downwards. 6. Experiments and Observations touching the Preservation and Destruction of (Eggs, Apples, and other) Bodies by Cold. 7. Experiments touching the Expansion of Water and Aqueous Liquors by Freezing. 8. Experiments touching the Contraction of Liquors by Cold. 9. Experiments in Consort, touching the Bubbles, from which the Levity of Ice is supposed to proceed. 10. Experiments about the Measure of the Expansion and the Contraction of Liquors by Cold. 11. Experiments touching the Expansive Force of Freezing Water. 12. Experiments touching a New way of estimating the Expansive