THE SIDEREAL UNIVEKSE. 751 



diameter, and the gaping mouth of the volcano of Aris- 

 tillus, still more prodigious, is ten leagues from one edge 

 to the other! Our glasses enable us to see these extinct 

 craters in such proportions, that none of their details 

 escape us ; whilst, were we on the moon, our telescopes, 

 according to Humboldt, would scarcely enable us to make 

 out terrestrial volcanoes. 



Seen from the earth many lunar volcanoes appear very 

 much depressed, and the edges of their craters resemble 

 so many flattened rings, projecting very little above the 

 plains. Some regions are so riddled with them that their 

 mouths touch. Others surmount lofty summits, and their 

 crenellated ramparts surround enormous excavations, 

 Avhich pierce deep into the aiiountains below the level of 

 the plains. 



Formerly the dark patches which cover part of the 

 moon's surface were considered as representing lunar seas, 

 but at present men are disposed to look upon them as only 

 immense plains. The first astronomers gave them names 

 full of poetry. There was the Sea of Tranquillity, the Sea 

 of Clouds, the Sea of Nectar, the Ocean of Tempests, and 

 the Sea of Serenity. 



The rocky and shattered soil of our satellite is perfectly 

 bare ; not a blade of grass grows there, not a flower opens. 

 Totally deprived of water and air, life is an impossibiHty. 

 A threefold death would overtake the least animal that 

 happened to alight there; a squirrel would perish of 

 hunger, thirst, and asphyxia ! In these C(jld and horrid 

 realms of the moon, everything is plunged in torpor and 

 silence; the echoes are mute, nothing alters the dull 

 monotony of the heavens, and the breath of a zephyr 

 never plays round the summits of the rugged mountains. 



By means of our instruments, which have now been 



