162 HISTORY OF GEOLOGY AND PALEONTOLOGY. 



moon on various scales. The largest chart was published on 

 1878 by Julius Schmidt, and with the work of this great 

 astronomer the older methods of investigation may be said to 

 have reached their highest point. 



A new era began with the application of photography to 

 the representation of moon landscapes. Warren de la Rue in 

 London, Draper and Rutherford in America, obtained photo- 

 graphs of remarkable beauty. But the earlier results of 

 photography were far exceeded when the astronomers of the 

 Lick Observatory in California made use of their giant lens. 

 The large number of landscapes obtained by this means are 

 now being compiled by Weinek in Prague, and a large Atlas 

 of the moon is being prepared. The English astronomers, 

 Nasmyth, Carpenter, Proctor, and Neison have also contri- 

 buted very greatly within the last twenty years to the know- 

 ledge of the constitution of the moon. 



From all these observations it has been proved that the 

 moon, unlike Mars, has no seas and canals, in short no water, 

 but possesses a wonderful array of mountains. With the naked 

 eye, darker-looking areas can be distinguished on the moon's 

 surface. From these rise numerous conical mountains, trun- 

 cated at the top and with deep craters, ring-shaped mountain- 

 ramparts, and magnificent, deeply-fissured mountain-massives, 

 whose summits are as high as 25,000 feet above the surround- 

 ing areas. In addition to these mountain-craters and rings 

 which indicate a volcanic origin, certain rents have been 

 discovered by Schroter in the plains, sometimes penetrating 

 the volcanic cones, and therefore clearly of subsequent origin. 

 A special geological interest attaches also to the presence of 

 light streaks radiating from the craters. Whilst the rents 

 might readily find an explanation as fractures due to contrac- 

 tion, the radially-arranged light-streaks present a difficult 

 question, and some authorities incline to regard them as 

 streams of lava, others again as evidences of sulphurous 

 springs. 



The surface conformation of the moon is by no means 

 constant in character. Schmidt in 1866 confirmed the dis- 

 appearance of an earlier crater, while Klein and Neison in 

 1877 saw the formation of a new crater. 



The American geologist Gilbert has contested the opinion 

 generally accepted at the present day, that the craters and 

 ring-shaped ramparts in the moon are volcanic in their origin. 



