THE SIDEREAL UNIVERSE. 715 



quicker. In his charming work on celestial marvels, M. Ca- 

 mille Flammarion says it would arrive at the surface of the 

 earth in 3 days, 1 hour, 45 minutes, and 13 seconds. 



The moon is in every part roughened with eminences of 

 different shapes, but they only very rarely group them- 

 selves into mountain chains comparable to those of our 

 globe. The Alps, Caucasus, and the Apennines represent 

 the principal ones. Certain isolated summits have received 

 the names of celebrated men, but those of past times have 

 been chosen in order not to excite any jealousy ; we travel 

 from the mountain of Aristotle to that of Hipparchus, from 

 that of Ptolemy to that of Copernicus. The astronomers 

 have very properly not forgotten their claims. 



The highest lunar mountains attain an altitude which sur- 

 passes most terrestrial elevations, a fact which may well 

 astonish us. Generally they do not rise beyond 22,750 feet. 

 But in proportion to the size of the planet, we may say that 

 the mountains in the moon are much loftier than those of 

 the earth. The summits of Mount Dcerfel are 24,700 feet 

 above the valleys which environ it, whilst the crest of Mont 

 Blanc only rises 15,632 feet above the level of the sea. 



Most of the mountains of our pale companion are of vol- 

 canic origin, and its surface has been so shattered by sub- 

 terranean fires that in many places the craters are heaped 

 up close beside each other. Probably no star was ever so 

 horribly torn by the fury of volcanoes. These even attain 

 proportions far beyond what is seen on our globe. Some of 

 those lunar craters are four or five leagues in diameter, and 

 the gaping mouth of the volcano of Aristillus, still more 

 prodigious, is ten leagues from one edge to the other ! Our 



