450 
NATURE 
[JULY 2, 1914 
slight acidification of the primary magma through (3) Botany... By. Prof: E. Brucker: ~ Pp. xv--1385. 
the solution of siliceous crust-rocks. 
In discussing the origin of the rocks forming 
the granitic clan, the author describes at con- 
siderable length cases in which granites are found 
in association with thick intrusive sheets or sills 
of basalt or gabbro. Thus the Purcell sills of 
British Columbia, which vary in thickness from 
roo ft. or less to’ about 1500 ft., are intrusive 
in thick felspathic and micaceous quartzites of 
Cambrian or earlier date. In several instances 
the top of a sheet consists ‘‘of a true biotite- 
granite (rarely hornblendic) passing downward 
into hornblendic gabbro.” Inclusions of quartzite 
surrounded by syntectic material occur in the 
gabbro, and the author maintains that the granite 
of these sills is the gravitative differentiate of a 
quartzite-gabbro syntectic. |The post-Cambrian 
batholithic granites are supposed to have been 
formed in a somewhat similar way. They are 
regarded as differentiates of crust-material dis- 
solved in large abyssal wedges injected from the 
basaltic substratum. The author, however, hesi- 
tates to extend his theory to all the large pre- 
Cambrian batholiths, and suggests that some of 
these may be re-fused portions of a primitive crust 
of granitic composition, the necessary heat having 
been supplied by radio-activity. Although he 
refers more than once to radio-activity, this is the 
only case in which he appears to regard it with 
any degree of favour as a source of the thermal 
energy manifested in igneous action. 
The origin of each of the other clans is dis- 
cussed at length, and the chapter dealing with 
alkaline rocks which are regarded as differentiates 
of syntectics of primary basalt and carbonates is 
of special interest: The concluding chapter deals 
with the application of the general theory to the 
igneous phenomena of the North American Cor- 
dillera. 
The book represents an interesting attempt to 
solve a problem of great complexity with the aid 
of our present knowledge, which is probably quite 
insufhcient for the purpose. 
INTRODUCTIONS TO NATURAL SCIENCE. 
(1) The Realm of Nature. An Outline of Physio- 
graphy. By Dr. H. R. Mill. Second Edition, 
largely re-written. Pp. xii+404. (London: 
John Murray, 1913.) Price ss. 
(2) Introduction to Biology. An Elementary Text- 
book and Laboratory Guide. By Prof. M. A. 
Bigelow and Anna N. Bigelow. Pp. ix +424. 
(New York: The Macmillan Company; London: 
Macmillan and Co., Ltd., 1913.) Price 6s. 
NO42335, VOE. O3)| 
(London: Constable and Co., Ltd., 
Price 25. net. 
(4) A First Book of Nature Study. By E. Sten- 
house. Pp. 148. (London: Macmillan and Co., 
Eickarors) ‘Price =1saieds 
(5) Weeds. Simple Lessons for Children. — By’ 
R. L. Praeger. With illustrations by S. Rosa- 
mond Praeger and R. J. Welch. Pp. x-4108. 
(Cambridge -University. Press,’ 1913.) Price 
6d. net. 
(6) Notes on the Natural History. of Common 
British Animals and some of their Foreign Re- 
lations. Vertebrates. By Kate M. Hall.) Pp: 
xli+289. (London: Adlard and Son, 1913.) 
ince, 35.~6d. net. 
“INCE 1891 Dr. Mill’s “Realm of Nature ” 
has been well known as one of the very 
best introductions to the study of the physical as- 
pects of the world we live in. Along with a few 
other books, such as Huxley’s “ Physiography,” it 
has occupied the first rank among text-books, and 
that place this new edition will retain. The 
reasons for this are to be found in the author’s 
quite remarkable clearness of head and _ style 
(which everyone who has heard him lecture has 
admired and envied), in his competence to deal 
with the many sides of the synoptic science of 
physiography, and also, we think, in the success 
with which he has made his facts illustrate prin- 
ciples. The book deals with the earth, the atmo- 
sphere, climate, weather, the ocean, the action of 
water on the land, the record of the rocks, the 
continents, the distribution of organisms, and man 
in nature. It has been thoroughly revised and 
brought up to date, but we are relieved to find 
that it remains in essence as we have known it 
for nearly a quarter of a century—with the same 
grip and terseness, the same absence of loose ends 
and dark corners—along certain lines one of the 
most educative books we have read. Though in 
a new dress it is an old friend, and we may be 
allowed with heartiness to wish it and its author 
well. 
(2) The introduction to biology proposed by 
Prof. Maurice A, Bigelow and Anna N. Bigelow 
is one which the authors have tested and found 
serviceable. It is an introduction to biological 
facts and ideas, and it is distinctive in selecting 
those facts and ideas which have a direct bearing 
on daily life. Thus we find much attention paid 
to the structure and functions of the human body, 
the biology of personal hygiene, organisms that 
affect human health, the economic relations of 
organisms, the reproduction of organisms, and so 
on. To our thinking, this is a partial introduction 
1913.) 
TS. 
(1) 
