THE MOON. 71 



twenty years after his appointment at Athens, 

 Schmidt worked at fixing the positions of lunar 

 objects, measuring the heights of mountains and 

 the depths of craters. An idea of his enthusiasm 

 in constructing his great chart may be gained 

 from the fact that he made almost a thousand 

 original sketches. 



Madler's dogmatic assertion that the Moon 

 was entirely a dead world was generally 

 believed until Schmidt made observations to 

 the contrary. From 1837 to 1866 the popular 

 opinion was that our satellite was an absolutely 

 dead world. Consequently there was little prog- 

 ress in lunar astronomy during those thirty 

 years. Although Madler's view was much 

 nearer the truth than the opinions of his 

 predecessors, it was also too positive. His 

 confident assertion, which was received with- 

 out hesitation, was never questioned until 

 Schmidt came upon the scene. To Schmidt 

 the Moon was not entirely dead, and it was 

 he who brought forward indisputable evidence 

 as to the existence of changes on its surface. 

 In October 1866 he announced that the crater 

 Linne had lost all appearance of such, and 

 that it had become entirely effaced. Lohrmann 

 and Madler had observed it under a totally 

 different aspect, as also had Schmidt himself 



