March 2, 1894. 
BOOK REVIEWS. 
Economic Geology of the United States; with briefer men- 
tion of foreign mineral products. By RALPHS. TARR, 
B.S., F.G.S.A., Assistant Professor of Geology at 
Cornell University. New York, Macmillan & Co., 
1894, 509 p., 27 figs., 2 plates. 
PROFESSOR TARR prepared this treatise to accompany 
his lectures on economic geology. In the preface he states 
that fereign localities have been referred to only where 
their importance or their bearing on the genesis of 
materials is noteworthy. The matter has been largely 
compiled. The author has himself studied in connection 
with official surveys many different areas in the United 
States, and one can see that he has brought much of his 
field observation to bear upon the treatment of his subject. 
The book deals with common rock and vein-forming 
minerals; rocks of the earth’s crust, which are illustrated 
by an abstract of the admirable tabulation of igneous 
rocks made by F. D. Adams on the basis of Rosenbusch’s 
system; physical geography and geology of the United 
States; origin of ore deposits; mining terms and methods; 
metalliferous deposits; non-metallic mineral products, 
including coal, petroleum, natural gas and asphaltum, 
building stones and cements, soils, clays, fertilizers, 
artesian wells and mineral waters, precious stones, abra- 
sive materials, salt, miscellaneous minerals and general 
summary of mineral production. 
The need of a hand-book of the economic geology of the 
United States has long been felt, and the works by Kemp 
and Lakes on ore deposits published in 1893 but partially 
covered the field which Professor Tarr has traversed in 
his generally lucid and engaging style. Itisa drawback 
to a treatise on this subject that so far as it depends upon 
the merits of its tabulated statistics and of its description 
of existing processes in the arts of mining and manufacture, 
so sure is it shortly, with the rapid improvement and 
alteration in mechanical devices, to be discarded as out of 
date. While Professor Tarr has brought the statistics of 
production down to so late a date as the year 1892, the 
scope of the work and the method of treatment will re- 
commend it for use as a text-book for undergraduate 
collegians long after its statistical information has ceased 
to be of practical utility. The real problems of economical 
geology, so far as they are distinct from those of geology 
proper, must usually be solved by the capitalist and pro- 
ducer. They are such questions as concern the relations 
of products and by-products, proximity to fuel, fluxes 
and markets, and are of themselves ever variable in their 
relations, though tolerably fixed in principle. While this 
side of the subject is generally least familiar to the 
geologist, and while our author makes no pretense in his 
headlines of discussing it, the student will find these im- 
portant considerations have not been overlooked in the 
treatment of particular products. 
The classification of ores used makes origin of primary 
and form of secondary significance. he detailed infor- 
mation which follows appears to fall clearly and easily into 
the groups formed upon this basis. 
The local geologist will note some unimportant mistakes, 
which have doubtless been perpetuated through compila- 
tion. Thusit is stated that afew thousand tons of coal 
are annually produced from the New England coal basin, a 
statement which was true several years ago. By a slip of 
the pen, on p. 124, the author makes the ‘‘ Huronian a 
division of the Archean,” instead of the Algonkian, as it 
is given in the table on p. 47. These errata may be 
sreadily corrected in asecond edition. The press-work is 
’ of high order; there is a copious index and an appendix 
of useful reference books. 
SC PENCE. 
123 
An Introduction to the Study of Petrology. By FREDERICK 
H. Harcu, Ph.D., F.G.S. London, Swan, Son- 
nenschein and Co.; New York, Macmillan and Co., 
2nd edit.) ill., 128 p., go cts. 
THOUGH not new in point of publication, this small 
work, now in its second edition, continues to be the only 
elementary treatise on petrology in our language. It is 
not intended for children but for those older students who 
may be entering upon the microscopic study of rocks, or 
for those workers in other fields who may wish to under- 
stand something of the manner and methods of modern 
research in lithology. The book is well illustrated with 
cuts, drawn in many instances from the works of Rosen- 
busch, Fouqué and Lévy, Bonney, and ‘Veall. 
The T. echmigque of Post-mortem Examination. By Lupwic 
HexkToen, M.D. Chicago, Ill., W. IT. Keener Co. 
In this little book of 170 pages Dr. Hektoen has 
supplied a lack in our literature. Here are given careful 
directions for ordinary post-mortem study, describing in 
detail necessary instruments, general methods of pro- 
cedure, general points to be noted and the proper methods 
of keeping data. The book is illustrated with forty-one 
figures, and is excellently designed for the purpose of 
guiding the inexperienced physician in making autopsies 
to the best advantage, obtaining the greatest results 
therefrom, and keeping his records in the most satis- 
factory manner. 
Le Cure. Par Paul Weiss, Ingénieur au Corps des Mines. 
Paris, Librairie J. B. Baillitre et Fils. 1894, 96 figs., 
344 p. Cartonné sf. 
In this volume M. Weiss has presented a very useful 
work on copper, designed not particularly for specialists, 
but rather for engineers and others who desire a clear 
general understanding of the metal, either from the stand- 
point of its position in economic geology, its chemistry, 
or its metallurgy. The work is divided into three parts, 
the first of which treats, in brief but sufficient detail, of 
the origin of copper and of its ores, of its physical pro- 
perties and of its alloys. The second part treats of the 
metallurgy from the roasting of the ore to the refining of 
the last malte, including descriptions of the Bessemer 
copper process and of electro-refining. Part third describes 
the applications of copper, the market, the employment 
of the metal in electricity and finally the copper foundry 
and the manufacture of alloys, bronzes and brass. In 
this connection are given several reproductions of photo- 
graphs showing the well-known works of M. Weiller at 
Angouléme. Tables of tensile strength, limit of elasticity, 
etc., for the various alloys, complete the volume. In 
treating of the origin and formation of the ores of copper 
the author, naturally, may be, but with reason, rejects the 
exclusive lateral secretion theory, as advocated particu- 
larly by some German authors, in favor of a fumerole 
action contemporaneous with the solidification of the 
basic rocks, the final position of the mineral, or metal, 
however, being determined by the action of circulating 
waters. The chapter on the molecular structure of copper 
alloys, being principally the experiments of M. Guillemin, 
is one of the most interesting. The examination under 
the microscope, after etching a polished surface with an 
appropriate reagent, shows remarkable difference in molec- 
ular structure corresponding with differences in chemical 
composition. Some thirteen micro-photographs are re- 
produced in illustration of the text, and it may be added 
that throughout the book is most excellently illustrated 
and is thus given a decidedly increased value to the 
general reader. 
