274 Remews — Nasmytk and Carpenter on the Moon. 



Puy de dome, Sarcony, etc. These central cones, however, in the moon 

 never rise to the height of the encircling ramparts. Indeed so far 

 from there being any signs of recurring activity among the lunar 

 volcanos, the close packing of such a vast number of craters over 

 nearly the whole surface of the moon, frequently touching, but 

 rarely interfering with one another, goes far towards accrediting 

 the belief that they were all in eruption at the same time, or, at least, 

 within the same very limited, and that probably a very early period 

 of our satellite's existence. It seems certain that while the processes 

 which have communicated such infinite variety to the surface relief 

 of our globe, and are still performing the same useful function, have 

 always been in active operation, those which produced the con- 

 figuration of the moon were only in activity at a time incalcul- 

 ably remote from the present, and have remained inactive ever 

 since; that while the former is and always has been undergoing 

 continual superficial destruction and renovation, almost resembling 

 the phenomena of life in an organized being, the latter has been 

 since the date of its eruptive activity absolutely inert and inanimate, 

 an extinct planetary body, destitute alike of organic life and even 

 of inorganic movement, internal or external, active or reactive. 



Such indeed would seem to be the necessary result of the absence 

 of any atmosphere, as well as of water, upon the moon's surface — a 

 fact which can hardly be called in question as respects the present 

 time, seeing that no clouds or vapour have ever been detected there, 

 such as could not fail to be produced in abundance by the exposure 

 of any superficial moisture to fourteen days of continual sunshine. 

 That the same condition has existed from the first, or at all events 

 since tlie formation of the present surface of the planet, is also 

 rendered almost certain by the non-existence there of any marks of 

 erosion or denudation. The absence of an atmosphere and of water 

 by eliminating all meteoric agencies must, from the first, have 

 deprived the moon's surface of any covering by sedimentary and 

 transported materials, such as compose so large a portion of our 

 earth's outer envelope, and by their low conductivity greatly 

 reduce the rate at which its internal heat escapes by radiation 

 into space. The fact that no change has been observed by reliable 

 authorities in the superficial features of the moon through the last 

 two or three centuries likewise offers some assurance of the com- 

 plete cessation at present of all intestine movements affecting its 

 crust, of the character of those which we know to be continually 

 disturbing the face of our planet. Thus, though we may conjecture 

 that the origin of both was the same, — viz. from the condensation 

 of nebular matter, — it is evident that, through some cause, — whether 

 its comparatively small volume and gravitating force, or its alternate 

 exposure for fourteen days together to extremes of superficial tem- 

 perature due to solar heat, probably ranging from 300° F. above, to 

 200° F. below freezing-point, or the excentricity of its axis of rota- 

 tion, or other unknown circumstance, — the present condition of the 

 moon is very dissimilar from that of our earth, and the analogy 

 observed in some of its main features must not lead us to infer that 



