REVIEWS 407 
in somewhat different form with such marked success in the Carnegie 
Institute of Washington. One cannot but feel that Doelter’s attitude 
with reference to some of the work of the American school is unfortunate. 
Of particular interest, however, are the sections on electrical conductivity, 
on specific heat and latent heat of fusion, and on the relation of the whole 
subject to rock crystallization and differentiation. While certain parts: 
of the article are to be found in Doelter’s earlier books, it is by far the 
most complete and valuable résumé of the subject of silicate fusions that 
we yet possess. 
The services of Dittrich have been secured to deal with methods of 
analysis of the various classes of minerals. Vogt contributes an article 
on slags, and treats the subject rather more from the standpoint of the 
metallurgist than in his previous works with which petrologists are 
acquainted. It need only be added that the publishers seem to have 
fully realized the value of the Handbuch, and have spared no pains to 
make it a most attractive addition to a reference library. May the other 
three volumes very soon find their place beside this one on the library 
shelves. 
RC WArtthAce 
An Introduction to the Mathematical Theory of Heat Conduction, with 
Engineering and Geological Applications. By L. R. INGERSOLL 
and O. J. ZoBEL. Boston: Ginn & Co.,1913. Pp. 171, 24 figs. 
Although primarily intended for students of physics, this textbook 
contains, as its subtitle would suggest, a certain amount of material that 
has an important bearing on geological problems, especially those that 
have to do with the transfer of heat. In chap. vii, on “‘ The Linear Flow 
of Heat,” some of the sections bearing on geology are: thawing of frozen 
soil, cooling of lava under water, cooling of the earth with and without 
radioactive considerations, and estimates of age, heat sources, tempera- 
tures in decomposing granite. Chap. vii, ““The Flow of Heat in More 
than One Dimension,” treats the cooling of a laccolith and the cooling of 
a sphere by radiation. 
The conclusions on the nature and rate of progress of a heat wave 
traveling from a laccolith into limestone throw interesting light on the 
conditions of the contact metamorphism of limestone and the develop- 
ment of ores at such points. The slow advance of the heat wave, allow- 
ing as it does a difference of temperature of about 50° C. at points 200 
meters on either side of the contact, at the end of 10,000 years, must be a 
