100 
NATURE 
[Fune 4, 1885 
cules is strongly insisted on throughout this book. When 
we know nothing of these relations the author does not 
hesitate to tell us so. Thus, regarding the formula of 
benzene, as commonly written with successive double and 
single bonds, he says (p. 239) :—‘ This formula, however, 
expresses something about which we know nothing, and 
concerning which it is difficult at present to form any 
conception. The simpler formula [/.e. the hexagon with- 
out any double bonds] leaves the question as to the 
relation between the carbon atoms entirely open, as it is 
in fact.” And again, speaking of the structure of the 
molecule of ethylene, Prof. Remsen remarks (p. 213) :— 
“As regards the relations between the two carbon atoms 
of ethylene we know nothing, save that it is probably 
different from that which exists between the carbon atoms 
of ethaxe.” 
A most instructive example of the methods pursued in 
organic chemistry, and at the same time of the scientific 
method of inquiry, is to be found on pp. 318-321, where 
the reactions of phenol-phthalein are discussed. The 
facts are given, but they seem only facts until some light 
is shed on them by the appearance in one reaction of 
triphenylmethane, a substance already familiar to the 
student. The student is shown how “this suggests that 
all the substances [he has been examining] are derivatives 
of this fundamental hydrocarbon.” And he is asked to note 
how easily, when this conception has once been formed, 
the interpretation of all the reactions follows. 
Many other admirable illustrations of the scientific 
method of inquiry are to be found throughout the book. 
I would especially draw attention to the simple but 
thoroughgoing treatment of the “equivalency of the 
hydrogen atoms” in the molecule CH, (pp. 28-29), and 
in the molecule C,H, (pp. 234-236). It is on subjects 
such as are discussed in the pages referred to that 
the chemical student so frequently suffers shipwreck. 
If he will use this little book by Prof. Remsen as 
his pilot, and will keep a good look out as he proceeds, 
he may hope to pass the shoals of the hexagon-formula, 
and the shallows of the ortho-, meta-, and para-derivatives 
of benzene. 
The author of this book deserves the thanks of all 
chemical teachers who have tried to teach organic chem- 
istry to beginners for the clear and short directions which 
he gives for preparing the more important compounds of 
carbon. The book may well be used as a laboratory 
guide, no less than as an introduction to the science of 
organic chemistry. 
Prof. Remsen has already done good service to the 
science of which he is a student, by publishing his 
“Principles of Theoretical Chemistry ;” he has now 
given us a book which must be of great use in advancing 
the study of organic chemistry ; could he not supplement 
these by an elementary but scientific treatise on inorganic 
chemistry ? M. M. PaTtrison MUIR 
MINERALOGY IN CALIFORNIA 
Fourth Annual Report of the State Mineralogist of 
California. By H.G. Hanks. $8vo, pp. 410. (Sacra- 
mento; State Printer.) 
A UTHOUGH a systematic geological investigation of 
= the State of California has been commenced at dif- 
ferent times since 1853, the Legislature has generally got 
tired of providing the funds after a few years’ continu- 
ance, and the work has been stopped. The most notable 
effort towards the provision of a complete geological 
description of the State was that made by Prof. J. D. 
Whitney, who, with a body of assistants, including men 
of the highest attainments in every collateral branch of 
natural science, carried on the survey from 1860 to 1873, 
when it was suddenly discontinued, to the great regret of 
scientific men both in America and Europe. No attempt 
to continue or supplement Prof. Whitney’s work was 
made until 1880, when the author was appointed State 
mineralogist with the object of investigating questions 
more particularly connected with mining industry than 
with geology in the larger sense. The author during his 
period of office, which appears to be terminable and held 
for four years only, has founded a valuable mineral 
museum and library, more than 6000 specimens illus- 
trative of the mineral deposits of the State having been 
collected and arranged. These do not, however, appear 
to be very sumptuously housed, as the author calls atten- 
tion to the danger from fire, “as well as other incon- 
veniences, such as the prevalence of ammoniacal and 
hippuric odours, and the disturbance of arranged speci- © 
mens in the cases by the jarring made by the hoisting of 
hay by tackles attached to the underside of the museum 
floor. The California State Museum is well worthy of a 
good and thoroughly fireproof building.” With the latter 
opinion our readers will no doubt heartily agree. 
Besides the work of organising the museum the author 
has published annually a report upon some branch of 
mineral industry as carried out in the State—for instance, 
that for 1883 was largely devoted to the borax deposits 
of the mud lakes in the interior of the State. The present 
volume, described as the fourth and last report of the 
State mineralogist, is mainly devoted to a catalogue and 
description of the minerals of California as far as they 
are yet known. This is alphabetically arranged, and 
contains descriptions of the composition physical proper- 
ties and uses of the different species, together with de- 
tailed information as to localities, and methods of working 
in the more important ones. Altogether 161 different 
species are described as having been found in California, 
but this number will no doubt be considerably increased 
by future explorers. At the present time, in addition to 
gold; mercury, petroleum, and borax are the chief pro- 
ducts of importance, although as regards all of them the 
prevailing complaints of over-production and unre- 
munerative prices appear to be as prevalent as in less 
favoured localities in the Old World. The condition of 
the gold-mining industry appears to be a very healthy 
one, for although the enormous annual yield, ranging 
from 10 to 13 millions sterling in 1850-55, has diminished 
to 3 and 44 millions in the past four years ; the increased 
facilities for working render it possible to handle at a profit 
rock not containing more than 12s. worth of gold in the 
ton ; while in the earlier days 20 dollar (80s.) rock was not 
considered to be worth removal. The total value of the 
gold raised in California since 1848 is estimated at above 
230,000,000/. in value, which if reduced to a single mass 
would be contained in a cube 14 feet 4 inches in the side. 
Although the work is essentially a compilation, it is 
well arranged, and will be of great use to those interested 
in Californian minerals. A general introduction on the 
—— eS ae ee Yo 
ee 
. 
