72 A CENTURY'S PROGRESS IN ASTRONOMY. 



from 1840 to 1843. There was great excite- 

 ment in the astronomical world on Schmidt's 

 announcement, and many astronomers denied 

 the change, although Schmidt's observation was 

 confirmed by Secchi and Webb. The evidence 

 in favour of it preponderated, and very few 

 observers now consider the Moon's surface to 

 be absolutely changeless. 



In 1865 Schmidt had begun to arrange his 

 observations on the Moon into the form of a 

 chart. At first he decided to have a chart of 

 six feet diameter, divided, like that of Madler, 

 into four sections. But in April 1868, on 

 making an estimate of the value of such a 

 chart, he was dissatisfied, and determined to 

 construct a map of the same size divided into 

 twenty-five sections instead of four. He began 

 the work in 1868, and after six years the 

 great map was completed. After some delay 

 the German Government undertook to issue the 

 chart at their expense, and it was published in 

 1879, after fourteen years of preparation. It 

 contained no fewer than 30,000 objects, and its 

 completed diameter was six feet three inches 

 more than double the size of any previous 

 map of the Moon. Indeed, it was probably 

 the greatest contribution ever made to lunar 

 astronomy. Schmidt lived only a few years 



