90 A CENTURY'S PROGRESS IN ASTRONOMY. 



Of all the planets Mars has been most studied 

 during the nineteenth century. Many illustrious 

 astronomers have devoted years to the study of 

 the red planet, with the result that more is 

 known of the surface of Mars than of any other 

 celestial body, with the exception of the Moon. 

 After the time of Herschel, the leading students 

 of Mars were Beer and Madler, who carefully 

 studied the planet from 1828 to 1839. They 

 identified at each opposition the same dark spots, 

 frequently obscured by mists, and they also made 

 the most accurate determination of the rotation 

 period, which they fixed at 24 hours 37 minutes 23 

 seconds. This estimate was confirmed in 1862 by 

 Friedrich Kaiser (1808-1872) of Leyden, in 1869 

 by Richard Anthony Proctor (1837-1888), and 

 in 1892 by Henricius Gerardus van de Sande 

 Bakhuyzen (born 1838), director of the Leyden 

 Observatory. In 1862 Lockyer identified the 

 various markings seen by Beer and Madler in 

 1830. The other great names in Martian study 

 prior to 1877 are Angelo Secchi and William 

 Rutter Dawes (1799-1868), who studied Mars 

 from 1852 to 1865 and secured a very valu- 

 able series of drawings. These drawings were 

 used by Proctor for the construction of the 

 first reliable map of Mars, which was published 

 in 1870 in his work, 'Other Worlds than Ours/ 



