272 Revieius — Nasmyth and Carpenter on the Moon. 

 li IE "V IIE ^w s. 



I.— The MooN.i 



THE work of which the title appears below is a magnificent con- 

 tribution to the study of the phenomena of our satellite, 

 illustrated by most interesting and instructive photographs of the 

 entire visible disc and magnified portions of its principal features. 

 The accompanying verbal descriptions, and the disquisitions on the 

 character and probable origin of these features, are given with a 

 fulness of detail and clearness of style which cannot fail to render 

 the work acceptable to both the scientific and general public. I will 

 not, however, pretend to review such a work in its entirety, for 

 which the limits to which I must confine myself would not suffice. 

 But it may be allowed me, perhaps, to notice briefly such portions 

 as bear upon the seemingly volcanic character of the lunar surface, 

 and may possess an interest to the readers of the Magazine. 



It is now fifty years since, upon my reading a paper to the Geo- 

 logical Society on the Phlegraean fields near Naples, illustrated with a 

 sketch-map of its several crater-hills, Sir John Herschel, in the 

 discussion that followed, expressed his conviction that many portions 

 of the moon's surface must have had a similar volcanic origin. And 

 he subsequently declared that the lunar mountains " expressed the 

 volcanic character in its highest perfection." Nevertheless there 

 exists sufficient difference between the volcanic manifestations in the 

 two planets to justify the opinion of a corresponding difference in 

 the conditions under which they were produced, and to render their 

 comparison an interesting subject of study to geologists, no less than 

 selenologists. Having myself paid special attention to the pheno- 

 mena of terrestrial vulcanicity, I will venture to offer some remarks 

 that suggest themselves in reference to the diversities alluded to 

 above, and their probable causes. 



1. Lunar craters. No one can have examined the moon's surface 

 with a telescope of even moderate magnifying powers without 

 being struck by the prodigious number of crater-like hollows with 

 which it is pitted, as thickly as ever was a human face with the 

 marks left by the small-pox. They are in fact countless, and of 

 all sizes, from circular or nearly circular plains — 20, 30, even 70 — 

 and if the larger dusky spaces usually called seas are to be also 

 reckoned as craters, from their approximating to a circular outline — 

 more than 300 miles in diameter, each surrounded by ramparts often 

 several thousand feet in height, generally precipitous towards the 

 interior, but having rugged outer slopes — down to cones so minute 

 as to be almost invisible even with the aid of the most powerful 

 instruments, each likewise encircling a cup-shaped hollow. These 

 minor craters are generally arranged in lines, often radiating from 

 some central point on which the eruptive force seems to have been 

 exceptionally violent. 



The other characteristic features of the lunar disc, as described by 



1 The Moon, considered as a Planet, a "World, and a Satellite, by James Nasmyth, 

 C.E., and James Carpenter, F.E.A.S. (John Murray, Albemarle Street, 1874.) 



