ASTRONOMY. 



flourished six centuries before tire birth 

 of Christ, predicted, according- to the 

 testimony of Herodotus, an eclipse of the 

 sun. Hence it should seem, that in those 

 early days, the globular figure of the 

 earth had been, by the learned, investi- 

 gated and credited. This being 1 known, 

 its magnitude would also soon be disco- 

 vered: the solution of this apparently 

 difficult problem engaged the attention 

 of many great men about the same peri- 

 od ; and though the measures which they 

 have given are wide of the truth, and 

 oven very different from one another, yet 

 this mav be imputed to the inaccuracy of 

 their instruments, and the want of ma- 

 thematical knowledge, rather than to the 

 impracticability in the thing itself. With- 

 out, however, entering upon this subject, 

 we may observe, that the universe in gene- 

 ral, as well as the solar system in particu- 

 lar, are in some mei'sure connected with 

 the motion of the globe that we inhabit. 

 By the universe may be understood, the 

 whole frame of nature to the utmost ex- 

 tent of the creation, and by the solar sys- 

 tem is meant, that portion ofit which com- 

 prehends the sun, planets, satellites, and 

 comets. Of this system the sun is suppos- 

 ed to be in the centre, round which there 

 are eleven planets continually revolving. 

 If we can form a notion of the manner 

 in which the earth moves, we shall easily 

 conceive the motions of all the rest of 

 the planets, and by that means obtain a 

 complete idea of the order and economy 

 of the whole system. And in order to 

 this, nothing more is necessary than to 

 consider the common appearances of the 

 heavens, which are constantly presented 

 to our view, and attend to the conse- 

 quences. For since it is well known that 

 the sun and stars appear to move daily 

 from east to west, and to return nearly to 

 the same places in the heavens again in 24 

 hours, it follows, that they must really 

 move, as they appear to do, or else that 

 we ourselves must be moved, and attri- 

 bute our motion to them : it being a self- 

 evident principle, that if two things 

 change their situation with respect to 

 each other, one of them, at least, must 

 have moved. But if this change be ow- 

 ing to the revolution of the stars, we must 

 suppose them to be endowed with a mo- 

 tion so exceedingly swift, as to exceed 

 all conception ; since it is now known, 

 by calculations founded on the surest ob- 

 servations, that their distances from us 

 are so immense, and the orbits they have 

 to. run round so prodigiously great, that 



the nearest of them would move at least 

 one hundred thousand miles in a minute, 

 Now as nature never does that in a com- 

 plicated and laborious manner, which 

 may be done in a more simple and easy 

 one, it is certainly more agreeable to rea- 

 son, as well as to the power and wisdom 

 of the Creator, that these effects should 

 be produced by the motion of the earth ; 

 especially as such a motion will best ac- 

 count for all the celestial appearances; 

 and at the same time preserve that beau- 

 tiful simplicity and harmony, which is 

 found to prevail in every other part of 

 the creation. And this argument will ap- 

 pear stiil more forcible, if we compare 

 the vast bulk of the celestial bodies with 

 the bulk of the earth. For it is now well 

 known, that the sun is above a million of 

 times larger than the earth ; and from the 

 best modern observations it appears, that 

 many of the stars are at least equally 

 large. It is much more probable, there- 

 fore, that the earth revolves round its 

 axis, with an easy natural motion, once in 

 24 hours, than that those immense bo- 

 dies should be carried from one place to 

 another with such incredible swiftness. 

 Nor is it any objection to this rotation of 

 the earth, that we are unable to perceive 

 it. For as the motion of a ship at sea, 

 when she sails swiftly over the smooth 

 surface of the water, is almost impercep- 

 tible to the passengers and company on 

 board, much more so must it be with such 

 a large body as the earth, which has no 

 impediments or obstacles of any kind to 

 meet with in its way, or to disturb its mo- 

 tion. And in a manner equally easy may 

 another objection be removed, which has 

 frequently been brought against this doc- 

 trine. It has been asserted, that if the 

 earth moved, a stone dropped from the 

 top of a tower, or any other high build- 

 ing, would not fall just at the bottom ofit, 

 as the building must have advanced con- 

 siderably forward during the time of the 

 fall. But this is evidently a mistake ; for 

 it is well known, by repeated experi- 

 ments, that if a body be projected from 

 another body in motion, it will always 

 partake of the motion of that other body. 

 Thus, a stone dropped from the top of a 

 mast, while the ship is under sail, is not 

 left by the vessel, but falls exactly at the 

 foot of the mast. And if a bottle of water 

 be hung up in the cabin, with its neck 

 downwards, it will empty itself drop by 

 drop, into another bottle placed exactly 

 underneath it, though the ship shall have 

 run many feet whilst each drop was in the 



