PETROLOGICAL ABSTRACTS AND REVIEWS 83 
Day, ARTHUR L., AND SosMAN, Rospert B. “The Melting-Points 
of Minerals in the Light of Recent Investigations on the Gas 
Thermometer, Am. Journ. Sci., XX XI (1911), 341-49. 
This article brings under one cover the previously published deter- 
minations of melting and other transition points made on the gas ther- 
mometer. One table contains the determinations that are considered 
accurate and another those that are only approximate. A bibliography 
of the original papers in which these results appeared is added. 
ALBERT D. BROKAW 
Ippincs, JosePH P. Rock Minerals, Their Chemical and Physical 
Characters and Their Determination in Thin Sections. Second 
edition, revised and enlarged. New York: John Wiley & 
Sons, 1911. 8vo, pp. Mii+617; figs. 500; and 1 colored plate. 
The issue of a second edition of Professor Idding’s book so soon after 
the first is an indication of its success. In this revised work but little 
change has made been in the first part; the insertion of a page and a 
half on pleochroic halos and the substitution of Michel-Lévy’s recent, 
for his old diagram of extinction angles on combined Carlsbad and albite 
twins, being all. The second part is increased by 66 pages by the addi- 
tion of about eighty minerals, chiefly those occuring in pegmatites and 
as segregated ores, representing extremes of magmatic differentiation. 
ALBERT JOHANNSEN 
LeBepeEw, P. “Experimentelle Untersuchung einiger binarer 
Systeme von Silicaten,”’ Annales de l'Institute Polytechnique 
Pierre le Grand a St. Pétersbourg, XV (1911), 690-720, figs. 
a+it. 
This article is in Russian with a two-page résumé in German. The 
studies are devoted to a diopside-olivine system and an anorthite- 
wollastonite system. In the first the eutectic point is reached with 40 
mol. per cent olivine; in the second with 30 mol. per cent anorthite. 
Freezing-point curves of mixtures are plotted. In the résumé no ques- 
tion is raised as to whether either of these systems is a simple binary 
system. In the opinion of the reviewer the second at least should be 
considered a ternary system—either a part of the CaQ—Al,O,-SiO, 
system studied by Shepherd and Rankin, or of a CaSiO;-CaAl.Si.06- 
ALSiO, system, neither of which is so simple as the diagrams and the 
German résumé seem to indicate. 
ALBERT D. BROKAW 
