82 A CENTURY'S PROGRESS IN ASTRONOMY. 



1800 noticed that the southern horn of the 

 crescent presented a blunted appearance, which 

 he attributed to the existence of a mountain 

 eleven miles in height. From observations of 

 this mountain he came to the conclusion that 

 the planet rotated in 24 hours 4 minutes. This 

 was afterwards reduced by Friedrich Wilhelm 

 Beqsel (1784-1846) to 24 hours 53 seconds. 



After the time of Schroter there was no 

 astronomer who paid much attention to either 

 Mercury or Venus until the arrival on the scene 

 of the most persistent planetary observer and 

 one of the foremost astronomers of the nine- 

 teenth century. Giovanni Virginio Schiaparelli 

 was born at Savigliano, in Piedmont, in 1835, 

 and graduated at Turin in 1854. Called to 

 Milan as assistant in the Brera Observatory in 

 1860, he became director in 1862, and there 

 for thirty-eight years he studied astronomy in 

 all its aspects, making a great name for him- 

 self in various branches of the science. In 

 1900 he retired from the post of director, and 

 pursues his astronomical researches in his 

 retirement. 



In 1882 Schiaparelli took up the study of 

 Mercury in the clear air of Milan. Instead of 

 observing the planet through the evening haze, 

 like Schroter and others, he examined it by day, 



