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time worth perusing. We find it in serer- 

 al literary periodicals without credit. 



At the time of the birth of Mithradates, 

 one hundred and thirty years before Christ, 

 we have an account of a comet whose mag- 

 nitude muht have been far beyond anything 

 subsequently seen, as its splendor is said to 

 have surpassed that of the sun. In the 

 years two hundred and forty-eight, three 

 hundred and twenty-four, and three 

 hundred and ninety -nine of the Chris- 

 tian era, remarkable comets are record- 

 ed to have appeared; and in the year 

 one thousand and six one is described as 

 presenting a frightful aspect, exhibiting an 

 enormous curved tail, in the form of a 

 scythe. The appearance of the comet of 

 fourteen hundred and fifty-si^ spread eon- 

 aternation throughout Europe. The same 

 comet returned again in fifteen hundred and 

 thirty-one and sixteen hundred and seven ; 

 and it is recorded that, in sixteen hundred 

 and thirty, a wonderful comet appeared, 

 which, by its splendor and swiftness, excited 

 the deepest interest thro;jghout the world. 

 Newton examined this remarkable comet 

 with great attention, and was led, by the 

 general laws of the motion of bodies in free 

 space, as well as by his own particular ob- 

 servations, to conclude that the orbits of 

 comets must, like those of the planets, be 

 ellipses, having the sun in one focus, but far 

 more eccentric, and having their aphelions, 

 or greatest distance from the sun, far more 

 remote in the regions of space. The idea 

 thus thrown out by Newton, as also the ob- 

 servations upon comets made by Tycho 

 Brahe, were taken up by Dr. Halley, who 

 collated the observations which have been 

 made, touching the appearance and aspect 

 of comets from the primitive ages down to 

 his own time, and found that, with but few 

 exceptions, they had passed within less than 

 the earth's shortest distance from the sua, 

 Bome of them within less than one-third of 

 it, and others about one half. He examin- 

 ed with much care the comet of sixteen 

 hundred and eighty-two, and diecovered a 

 wonderful resemblance between it and the 

 comets of fourteen hundred and fifty-six, 

 fifteen hundred and thirty-one and sixteen 

 hundred and seven. The time of the ap 

 pearance of the comets had been at nearly 

 regular intervals, the average period being 

 seventy-five and seventy-six years. Their 

 distance from the sun when in perihelion 

 varied but little from each other. The in- 

 clinations of their orbits to that of the earth 

 had also been nearly the same — between 

 seventeen and eighteen degrees; their mo- 



tions had all been retrograde. Putting 

 these together. Dr. Halley came to the con- 

 clusion that the comets of fourteen hundred 

 and fifty-six, fifteen hundred and thirty-one, 

 sixteen hundred and seven and sixteen 

 hundred and eighty-two, were re-appear- 

 ances of one and the same comet. The va- 

 riations in the time of its revolution around 

 the sun having been something like fifteen 

 months, was accounted for by him upon the 

 supposition that the form of its orbit had 

 been altered by the attraction of the remote 

 planets, Jupiter and Saturn, and passed 

 near them; and he thereupon predicted that 

 its next appearance would be in the year 

 seventeen hundred and fifty-seven or seven- 

 teen hundred and fifty-eight; and its actual 

 re-appearance in seventeen hundred and 

 fifty-nine, according to this prediction, es- 

 tablished the fact decidedly, that they were 

 regular and permanent bodies, obeying the 

 general laws of matter. The only difficulty 

 which remained in arriving at a greater de- 

 gree of accuracy in calculating the return 

 of comets was on account of the disturbance 

 to which they are exposed from the other 

 bodies of the solar system. This was over- 

 come, in a good measure, after the death 

 of Dr. Halley, by the calculations of D'- 

 Alembert, Encke and Clairault, in regard 

 to the length of time this comet would be 

 retarded by the attraction of Jupiter. The 

 latter Professor, (Clairult,) read his investi- 

 gations upon this point to the Academy of 

 Science, in November, seventeen hundred 

 and fifty-eight; and in a little more than a 

 month afterwards, Halley's comet made its 

 appearance, and it reached its perihelion on 

 the thirteenth of March, seventeen hundred 

 and fifty-nine — being thirty days earlier than 

 he had calculated. Subsequent calculations 

 enabled him to reduce the error to nineteen 

 days. The perihelion passage of the same 

 comet, on its return in eighteen hundred 

 and thirty-five, was predicted within nine 

 days of its actual occurrence — a most aston- 

 ishing approximation to trijth, when it is 

 remembered that this body, far as it pene- 

 trates into space, never, even at the remot- 

 est point of its orbit, escapes from the sensi- 

 ble influence of the planet Jupiter. 



Besides the comet of seventeen hundred 

 and fifty-nine, of which there have been five 

 authenticated returns, there are several 

 others of which something like a return may 

 be traced at long intervals. One of these 

 passed its perihelion at about eight o'clock 

 on the morning of the sixth of July, twelve 

 hundred and sixty four, and again at a little 

 past eight o'clock on the evening of the 



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