THE MOON. 



Among the singular remarkable appearances upon the moon, is that of a 

 system of rays which appear to diverge from the crater-shaped ridges. One of 

 the most remarkable of these is exhibited in the appearance of the mountain 

 called Tycho. At the time of full moon, these appearances generally cast 

 very broad, brilliant bands, issuing from all sides of the crater, and stretching 

 to a greater or less distance, sometimes extending over a space of several hun- 

 dred miles. Two characteristics of these singular bands necessarily attract no- 

 tice. First, the light they throw is exactly of the same kind as that reflected 

 from the edge of the crater itself, and from the lowest part of the chasm ; so 

 that we must suppose that the matter forming them had the same origin and 

 source as the other portion of these mountainous formations. Secondly, it will 

 be observed that they hold their course without being interrupted by other for- 

 mations on the lunar surface. If, instead of a general rugged surface, the 

 face of the moon had been one unbroken plane, the course of these radiating 

 lines could not have been less disturbed, except that they accommodate them- 

 selves to the contour of the surface ; if they meet a valley, they bend with it ; 

 if a precipitous mountain, they rise with it precipitously ; and then pursue 

 their previous path. 



Before we dismiss the mountainous character of the moon's surface, it may 

 be well to state that the heights of these mountains, and the depths, in many 

 cases, of their cavities, have been pretty accurately ascertained by the meas- 

 urement of their shadows. It is generally stated that they are higher 

 than the mountain ranges of the earth. This, in a literal sense, is not true. 

 The lunar mountains do not attain to the actual height of some of the highest 

 of the terrestrial ranges ; but, considering that the moon is a globe on a scale 

 one fourth that of the earth, it may be truly stated that, according to the relative 

 sizes of the globes, the lunar mountains are considerably higher than those of 

 the earth. 



It is not the mere height of these mountains that so forcibly commands at- 

 tention ; it is their universal prevalence. 



At the early epochs of telescopic discoveries, when the moon was examined- 

 by telescopes of inferior power, extensive regions were observed upon it, which 

 seemed to be level surfaces, and which were therefore mistaken for seas. These 

 regions in the lunar surface have received names, every conspicuous moun- 

 tain being designated by a peculiar title, names were also given to those ap- 

 parent level portions, such as the Mare Imbrium, &c. As the power of the 

 telescope was improved, it soon became apparent that regions supposed to be 

 seas, were covered with asperities and inequalities, less indeed in elevation 

 than other parts of the moon, but still considerable. Every augmentation of 

 power which the telescope received, only adds fresh proof that there is no por- 

 tion of the moon absolutely level, and consequently that there does not exist 

 upon it, at least on the visible hemisphere, a collection of water. 



The celebrated telescopic view of the moon produced by the labors of Beer 

 and Madler, to which I have more than once referred, is exhibited on a re- 

 duced scale in the frontispiece of this volume. The mere inspection of that 

 drawing will afford abundant evidence to corroborate the statements which 

 have been here made ; more especially, if it be remembered that minute por- 

 tions of that view, where no inequalities are exhibited, will show innumerable 

 inequalities if submitted to an examination with a still higher magnifying 

 power 



I annex here two highly-magnified views of detached portions of the lunar 

 surface, supplied by the observations of Madler. In these the prevalence of 

 the crater form is especially conspicuous. The names of the more remarkable 

 mountains are here inserted. 



