THE MOON. 153 



Bents a great contrast to the South Pole, entirely covered with 

 mountains. Here lofty peaks shine during whole lunations 

 in eternal light, in the strictest sense of the word ; they are 

 true light islands, which become perceptible, even with feeble 

 magnifying powers.* 



As exceptions to this type of circular and annular configu- 

 rations, so universally predominant upon the Moon, are the 

 actual mountain-chains which occur almost in the middle of 

 the northern half of the Moon {Apennines, Caucasus, and 

 Al})s). They extend from south to north in a slight curve to- 

 ward the west, through nearly 32° of latitude. Innumer- 

 able mountain crests and extraordinary sharp peaks are here 

 thronged together. Few annular mountains, or crater-like 

 depressions, are intermingled (Conon, Hadley, Calippits), 

 and the whole resembles more the configuration of our mount- 

 ain-chains upon the Earth. The lunar Alps, which are in- 

 ferior in height to the lunar Caucasus and Apennines, pre- 

 sent a remarkable bro.id transverse valley, which intersects 

 the chain from southeast to northwest. It is surrounded by 

 mountain peaks which exceed in height that of Teneriffe. 



The relative height of the elevations in proportion to the 

 diameters of the Moon and the Earth, gives the remarkable 

 result, that since in the four times smaller satellite the high- 

 est peaks are only 3836 feet lower than those of the Earth, 

 the lunar mountains amount to ¥ i ¥ , the mountains on the 

 Earth to tjVt °f the planetary diameters. f Among the 1095 

 points of elevation already measured upon the Moon, I find 

 39 are higher than Mont Blanc (16,944 feet), and six higher 

 than 19,000 feet. The measurements were effected either 

 by light tangents (by determining the distance of the illumin- 

 ated mountain peak on the right side of the Moon from the 

 boundary of the light) or by the length of the shadows. The 

 former method was already made use of by Galileo, as is seen 

 from his letter to the Father Grienberger upon the Montu- 

 osita della Lu?m. 



According to Madler's careful measurements by means of 

 the length of the shadows, the culminating points of the 



* Madler, Astron., p. 166. 



t The highest peak of the Himalayas, and (up to the present time!) 

 of the whole Earth, Kinchin- junga, is, according to Waugh's recent 

 measurement, 4406 toises, or 28,178 English feet; the highest peak 

 among the Moon's mountains is, according to Madler, 3800 toises (ex- 

 actly four geographical miles). The diameter of the Moon is 1816, 

 that of the Earth 6872 geographical miles ; whence it follows for the 

 Moon ¥ i x , for the Earth yy-g-p 



G 2 



