338 Review of Allen’s Mechanies. 
higher than the surface of the ground in an extensive surrounding 
country. Hence by sinking a shaft that may penetrate this stratum, 
a flow of water would be obtained at the surface of the ground. 
Another observation may be made with regard to the vapor exha- 
lations from the earth. In the winter,* the earth receives no water 
by rains, yet the surface of the ground, in cold latitudes, obtains 
moisture sufficient to be frozen into a solid crust; and all springs and 
wells give a full discharge of water. Rivers that are supplied by 
springs, are also found to contain more water in winter than summer, 
although nothing is received from the surface of the ground. 
Art. X.—The science of Mechanics as applied to the present m- 
provements in the useful arts in Europe, and in the United States : 
adapted as a Manual for Mechanics Re eee 3 by 
Zacuarian Auten. Providence, R. I. 
(Communicated.) 
“pats is the first work of the kind, of domestic origin, that has been 
put into the hands of our practical mechanics and manufacturers. 
Some of the subjects contained in it, have appeared in separate trea~ 
tises and in periodical journals, but no American book has hitherto 
been published, calculated to afford instruction in so many depart- 
ments of a manufactory and workshop, as the one before us. Rob- 
inson’s Mechanical Philosophy, and Brewster’s edition of Ferguson’ 8 
Mechanics, published in England, can seldom be procured in this 
country. Nicholson’s Operative Mechanic, and Gregory’s Mechanics, 
republished in Philadelphia, have served as books of reference to our 
millwrights and machinists, and in connexion with the Encyclope- 
pia, have been their principal sources of information. ‘These works, 
os contain a great amount of matter totally irrelevant to the 
i Pte eT) 
+The write doubtless intends the iinet regions, as in the winters of the 
A question will of course 
arise ¢ as to the an - the subterranean water, which affords the exhalations; and 
the writer inion, whether it is ultimately derived from percolation, 
as some geologists suppose, there may be great subterranean reservoirs water. 
This, however, will not militate against the author’s hypothesis, for from whatever 
moy be derived, pag Cat me rmation and con 
sation ofits vapor. ~Ea. 
