Geology and Mineralogy. 17 
Eltoro, 40 miles south of Los Angeles, California. The specimen 
weighed 525 grams, was very compact, quite highly polished, 
‘and pale apple-green in color. In fact, it was supposed to be 
jade; and, so far as appearance was concerned, it fully justified 
the supposition. Believing it to be either nephrite or jadeite, I 
had an analysis of it made by Mr. George Steiger, in the U. S. 
Geological Survey laboratory, which showed it to be really 
grossularite garnet. The data are as follows: 
Meas. Beth So 2 eee SL 37°54 
‘LENE OS Ce AP Pe TRIS SRA SS ES trace 
NO Pe ences. eee 3 22°84 
es Oy are ie eee Ue 79 
iS OR oe rn ee a °26 
IGG il Se are 17S SO 36°66 
1! G16 SO Se ne eee ee "44 
BMUANES Soo. oe eo cask! AS 
1 P10 ie DataSet tana Ope trace 
LOU 1 See Se ey 1°74 
100°40 
Specific gravity, 3°485. The loss on ignition includes a trace 
of carbonic acid. On treating 0°2 gram of the powdered min- 
eral with hydrochloric acid, evaporating to dryness, and then 
redissolving, about 16 per cent of alumina and 20 per cent of 
lime went into solution. In this respect the specimen is there- 
fore somewhat unusual. But as a garnet simulating jade it is 
certainly interesting. 
10. Physikalische Krystallographie und Hinleitung in die krys- 
tallographische Kenniniss der wichtigeren Substanzen von Pavun 
Grota. Dritte vollstindig neu bearbeitete Auflage. III Abthei- 
lung, pp. i-xvi, 529-783, Leipzig, 1895 (Wm. Engelmann).—This 
third part completes the revised edition of Professor Groth’s 
Physical Crystallography, already noticed on p. 74 of the last 
volume. It is devoted to a discussion of the methods of calcula- 
tion applied to crystals, and to the apparatus and methods of 
investigation in the departments of Crystallography and Physical 
Mineralogy. 'To those who are acquainted with the earlier edi- 
tions of the author’s work, it is unnecessary to say that these 
topics are treated with all desirable completeness and clearness 
and that the most recent and important improvements in instru- 
ments are fully described. 
