SEQUEL TO COPERNICUS. 275 



this opinion with his magnetic doctrines ; and especially endeavors by 

 that means to account for the precession of the equinoxes. But he does 

 not seem to have been equally confident of its annual motion. In a 

 posthumous work, published in 1651 (De Mundo Nostro Sublunari 

 Philosophia Nova), he appears to hesitate between the systems of 

 Tycho and Copernicus. 8 Indeed, it is probable that at this period 

 many persons were in a state of doubt on such subjects. Milton, at a 

 period somewhat later, appears to have been still undecided. In the 

 opening of the eighth book of the Paradise Lost, he makes Adam 

 state the difficulties of the Ptolemaic hypothesis, to which the arch- 

 angel Raphael opposes the usual answers ; but afterwards suggests to 

 his pupil the newer system : 



.... What if seventh to these 



The planet earth, so steadfast though she seem, 



Insensibly three different motions move ? 



Par. Lost, b. viii. 



Milton's leaning, however, seems to have been for the new system ; 

 we can hardly believe that he would otherwise have conceived so 

 distinctly, and described with such obvious pleasure, the motion of 

 the earth : 



Or she from west her silent course advance 

 With inoffensive pace, that spinning sleeps 

 On her soft axle, while she paces even, 

 And bears thee soft with the smooth air along. 



Par. Lost, b. viii. 



Perhaps the works of the celebrated Bishop Wilkins tended more 

 than any others to the diffusion of the Copernican system in England, 

 since even their extravagances drew a stronger attention to them. In 

 1638, when he was only twenty-four years old, he published a book 

 entitled The Discovery of a New World ; or, a Discourse tending to 

 prove that it is probable there may be another habitable World in the 

 Moon ; with a Discourse concerning the possibility of a passage 

 thither. The latter part of his subject was, of course, an obvious 

 mark for the sneers and witticisms of critics. Two years afterwards, 

 in 1640, appeared his Discourse concerning a new Planet ; tending to 

 prove that it is probable our Earth is one of the Planets: in which he 

 urged the reasons in favor of the heliocentric system; and explained 

 away the opposite arguments, especially those drawn from the sup- 



8 Lib. ii. cap. 20. 



