LUNAR VOLCANOES. 
119 
represent faithfully its structure. The strong shadows, which 
are visible under the telescope, are but faintly perceptible in 
this likeness. But what is particularly worthy of notice, are 
the lunar craters, which are represented by the circular projec¬ 
tions upon different points of her face. The stellated fractures 
or fissures produced by soulevements of her crust, are among the 
remarkable features of the portrait. 
In order that the student may locate the lunar volcanic peaks, 
I have copied a diagram from the Penny Cyclopedia, fig. 24, upon 
which the relations of many of their points may be observed at 
leisure. But I would particularly recommend the study of the 
moon’s surface by means of a good telescope. 
The arrangement of lunar volcanoes, like those of the earth, 
is very nearly in lines, which indicates their connection by 
means of passages beneath. Considering the mass of the moon, 
and the rapidity with which heat escapes into space, it is pro¬ 
bable volcanic action has long since ceased, and that its primal 
fires were long ago extinguished. 
The moon has neither an atmosphere or water upon her sur¬ 
face. The temperature of the moon is different from that of 
the earth. She has fourteen and three-fourths days of sunlight, 
and of course the same number of days (terrestrial) of darkness. 
Intense heat and cold succeed each other. The moon’s mass 
is of that of the earth, and the average density of her mate¬ 
rial 0*615 or t 6 q of the earth. Hence a body weighing six 
pounds at the earth, would weigh one pound at the moon, if 
each weight retained its terrestrial gravity. Some of her 
circular or cusp-shaped mountains exceed one and" a half miles 
in height. I have already spoken of their volcanic character. 
