6o8 
Analyses of Books. 
[October, 
thrown up by volcanic aCtion. Hence it becomes highly probable 
that the interior of the earth consists chiefly of metals in a free 
state. If this view is correct it points to a process by which our 
globe will be in the course of ages rendered incapable of main- 
taining life, as the oxygen of the air will be gradually absorbed 
by these vast masses of metal. 
As regards the physical condition of the earth’s interior, the 
author does not accept the hypothesis, once in great favour, that 
it consists of a mass of molten matter enclosed in a thin solid 
shell. Independent of the astronomical and physical arguments 
for the earth’s rigidity, amongst others that founded upon the 
absence of subterranean tides, he contends that if volcanic pro- 
ducts were supplied from one common reservoir in the interior of 
the earth, the lavas should exhibit a much greater similarity of 
composition than is actually the case. But he admits that none 
of the hypotheses concerning the earth’s interior is free from 
objections, and that we are not yet able to come to a final 
decision. 
As regards the internal heat of the globe and the causes of 
volcanic aCtion, we have also much to learn. Prof. Judd admits 
the rise of temperature as we bore deeper into the globe, and he 
even suggests that at no distant time “we shall draw extensively 
upon these supplies of subterranean heat.” But the increment 
of temperature is not uniform ; it varies in different parts as i : 5, 
and in not a few borings it has been found that the rate of in- 
crease after a time becomes slower. Thus in the well of Speren- 
berg, near Berlin, the rate of increase is i° F. for every 55 feet, 
during the first 1900 feet of descent, but for the next 2000 feet it 
diminished to i° F. for every 62 feet. A similar fad was ob- 
served at the well of Grenelle, at Paris. These phenomena do 
not agree with the assumption that in descending we are 
approaching a great focus of heat. 
On the other hand, in the Comstock Mine the rise of tempera- 
ture becomes accelerated at depths below 2000 feet. 
In abruptly concluding oure notice of this interesting work we 
may fairly pronounce it a most able and judicious production. 
The author carefully eschews rash theories, and knows how to 
suspend judgment where the necessary evidence is not forth- 
coming. 
Proceedings of the Literary and Philosophical Society of Liver- 
pool During the 69 th Session , 1879-80. No. XXXIV. 
London : Longmans and Co. Liverpool : D. Marples and 
Co., Limited. 
Of the papers selected by the Council a very considerable pro- 
portion fall outside our cognisance entirely. We may mention 
“ The Place and Power of Criticism,” by the President, Mr. E, 
