Light and Colour of the Mooiu 61 



dour the most brilliant craters. As to the real nature of the 

 moon, with the exception of some negative determinations, we 

 know nothing special or exact. We may at least, however, be 

 permitted, after the preceding investigations, to reject, as inad- 

 missible, and contrary to observation, the opinion that the 

 moon is entirely covered with ice or with snow, or is nothing 

 more than a compact mass of rocks. 



Regarding the luminous bands, Schroeter and preceding sele- 

 nographers have regarded them as chains and ranges of moun- 

 tains, but our investigations expressly contradict this opinion. 

 Herschel believes that they are streams of lava which have 

 issued from the great craters, and have spread themselves in 

 all directions.* Being ignorant of the forces which may be in 

 activity in the interior of the moon, we consequently cannot 

 bring forward the great altitude of the zone of Tycho, Coperni- 

 cus, &c., nor their other relations as to form and size, as decisive 

 objections against this opinion. But a current of lava ought, 

 more or less, like any other current, to tend towards the hol- 

 lows when descending from a height, and should follow the 

 sinuosities of the valleys ; or, should it be so powerful as to 

 force forward its route in a straight line, and not to be arrested 

 by ramparts of from 6000 to 10,000 feet of vertical elevation, 

 it should at all events fill up the hollows which lie behind these 

 ramparts, instead of simply continuing its progress, and leav- 

 ing every thing untouched to the right and left. If, for ex- 

 ample, we examine the bands which pass towards Stofler, Kies, 

 Bouillaud, Maginus, and other annular mountains, we shall 

 be easily convinced tha^, so far as it is a question of gra- 

 vitation merely, the lava or any other fluid could never follow 

 the courses which we have traced. 



Still less can it be thought that they are jets of continuous 

 light proceeding from a central point ; for the bands extend 



• Herschel, it is true, has no where so expressed himself in so many words ; 

 and perhaps he applied his remarks, not so much to the luminous bands, as to 

 the small mountain ramifications, which extend, for example, from Aristillus 

 and Autolycus, to the distance of jfrom eight to twelve miles. {Note by the 

 Axiihors.) 



