28 HISTORY OF FORMAL ASTRONOMY. 



tower? since the tower being carried from west 

 to east by the diurnal revolution of the earth, 

 the stone must be left behind to the west of the 

 place from which it was let fall. The proper 

 answer to this was, that the motion which the fall- 

 ing body received from its tendency downwards 

 was compounded with the motion which, before it 

 fell, it had in virtue of the earth's rotation : but 

 this answer could not be clearly made or appre- 

 hended, till Galileo and his pupils had established 

 the laws of such compositions of motion arising 

 from different forces. Rothman, Kepler, and other 

 defenders of the Copernican system, gave their 

 reply somewhat at a venture, when they asserted 

 that the motion of the earth was communicated to 

 bodies at its surface. Still, the facts which indicate 

 and establish this truth are obvious, when the sub- 

 ject is steadily considered; and the Copernicans 

 soon found that they had the superiority of argu- 

 ment on this point as well as others. The attacks 

 upon the Copernican system by Durret, Morin, 

 Riccioli, and the defence of it by Galileo, Lansberg, 

 Gassendi 10 , left on all candid reasoners a clear 

 impression in favour of the system. Morin at- 

 tempted to stop the motion of the earth, which he 

 called breaking its wings ; his Aim Terras Fractce 

 was published in 1643, and answered by Gassendi. 

 And Riccioli, as late as 1653, in his Almag&htm 

 Novum, enumerated fifty-seven Copernican 

 10 Del. A. M. vol. i. p. 594. 



