ikct. iv.] DISSERTATION SECOND. 139 



prepared the way for physical astronomy, and in these 

 ideas he was earlier than Descartes. 



The discoveries of Kepler were secrets extorted from 

 nature by the most profound and laborious research. The 

 astronomical discoveries of Galileo, more brilliant and im- 

 posing, were made at a far less expense of intellectual la- 

 bour. By this it is not meant to say that Galileo did not 

 possess, and did not exert intellectual powers of the very 

 highest order, but it was less in his astronomical discove- 

 ries that he had occasion to exert them, than in those 

 which concerned the theory of motion. The telescope 

 turned to the heavens for the first time, in the hands of a 

 man far inferiour to the Italian philosopher, must have un- 

 folded a series of wonders to astonish aud delight the 

 world. 



It was in the year 1609 that the news of a discovery, 

 made in Holland, reached Galileo, viz. that two glasses 

 had been so combined, as greatly to magnify the objects 

 seen through them. More was not told, and more was not 

 necessary to awaken a mind abundantly alive to all that 

 interested the progress either of science or of art. Galileo 

 applied himself to try various combinations of lenses, and 

 he quickly fell on one which made objects appear greater 

 than when seen by the naked eye, in the proportion of 

 three to one. He soon improved on this construction, and 

 found one which magnified thirty-two times, nearly as 

 much as the kind of telescope he used is capable of. 

 That telescope was formed of two lenses ; the lens next 

 the object convex, the other concave ; the objects were 

 presented upright, and magnified in their lineal dimensions 

 in the proportion just assigned. 



Having tried the effect of this combination on terres- 

 trial objects, )\: next directed it to the moon. What the 

 telescope discovers on the ever-varying face of that lurai 



