SEQUEL TO COPERNICUS. 413 



of the moon's surface ; the moon-like phases of the 

 planet Venus; the discovery of the satellites of 

 Jupiter, and of the ring of Saturn. These dis- 

 coveries excited at the time the strongest interest ; 

 both from the novelty and beauty of the objects 

 they presented to the sense ; from the way in which 

 they seemed to gratify man's curiosity with regard 

 to the remote parts of the universe ; and also from 

 that of which we have here to speak, their bearing 

 upon the conflict of the old and the new philo- 

 sophy, the heliocentric and geocentric theories. It 

 may be true, as Lagrange and Montucla say, that the 

 laws which Galileo discovered in mechanics implied 

 a profounder genius than the novelties he detected 

 in the sky : but the latter naturally attracted the 

 greater share of the attention of the world, and 

 were matter of keener discussion. 



It is not to our purpose to speak here of the 

 details and of the occasion of the invention of the 

 Telescope ; it is well known that Galileo constructed 

 his about 1609, and proceeded immediately to apply 

 it to the heavens. The discovery of the Satellites 

 of Jupiter was almost immediately the reward of 

 this activity: and these were announced in his 

 Nuncius Sidereus, published at Venice in 1610. 

 The title of this work will best convey an idea of 

 the claim it made to public notice : " The Sidereal 

 Messenger, announcing great and very wonderful 

 spectacles, and offering them to the consideration 

 of every one, but especially of philosophers and 



