APRIL 15, 1897 | 
NATURE 
aM 
on 
index. Though the book covers too wide a field to 
afford a thorough treatment of special subjects, it fur- 
nishes a useful, concise introduction for students to the 
general principles of hydraulics, and the machines | 
relating to water. 
The Story of the Chemical Elements. By M. M. Pattison 
Muir, M.A. Pp. 189. (London: George Newnes, 
Ltd., 1897.) 
THIS book forms one of a series constituting a “ Library 
of Useful Stories,” and the object of the author has been 
to “put forth in some kind of orderly sequence a few of 
the chief guiding conceptions of chemistry ” as exempli- 
fied by familiar things and phenomena. Mr. Muir deals 
with his subject in a philosophical spirit, but we fear he 
assumes too much of the same spirit in his readers for 
the book to prove really attractive to people unacquainted 
with chemistry. It is difficult to expound the elements 
of chemistry otherwise than by experiment—impossible, 
in fact, to do so satisfactorily—and we should imagine 
that the readers for whom the book is intended are of the 
kind that require very careful wooing. Nearly one 
quarter of the book is devoted to carefully marking out 
the distinction between elements and ‘not-elements,” 
and between physical and chemical change ; and though 
much pains have been taken to interweave homely and 
attractive illustrations, we doubt very much whether the 
desired end will be reached. Distinctions of the kind in | 
question cannot be said to be intrinsically interesting, | 
and we think that the author exaggerates both their im- 
portance and the nicety of treatment required for the 
main purpose of his book. The task attempted by Mr. 
Muir 1s, as already remarked, a hard one, and when we 
recall the opinions which he has so often expressed 
concerning the right method of teaching chemistry, 
we cannot suppose the task to have been entirely 
congenial. Bos: 
Physics: an Elementary Text-Book for University 
Classes. By Dr. C. G. Knott. Pp. vi + 351. (London: 
Chambers, 1897.) 
IN taking up such a book as that of Dr. Knott’s, one 
cannot help feeling that the attempt to treat such a subject 
as physics within the limits of a book of between three 
and four hundred pages, must be attended with extreme 
difficulty. When, on further perusal, we notice that this 
work contains references to such subjects as contours, 
determination of the mean density of the earth, the 
theory of the formation of murages both erect and in- 
verted—to mention only a few of those matters which 
the elementary text-book usually leaves out of consider- | 
ation—we are struck with amazement. - But though it 
might be said that Dr. Knott treats “de omnibus rebus 
et guibusdam aliis,’ he has succeeded beyond expect- 
ation in making his book not only readable but attrac- 
tive. To one who has read the subject in other works, 
or who has attended a series of lectures, it will prove 
most useful as a help to revising his knowledge and 
giving him a general view of the whole science, which 
every year makes it more difficult to obtain; and we 
feel certain that many a student of physics will be 
grateful to Dr. Knott for furnishing him with such a 
useful compendium. 
Le Déterminisme biologique et la Personnalité Consciente. 
By Félix Le Dantec. Pp. 158. (Paris: Alcan, 1897.) 
TuIs volume is a sequel of the author's “‘ Théorie nouvelle 
dela vie,” which was published last year. The most interest- 
ing feature of that theory was the doctrine that constructive 
activity of living substance was to be regarded as the chief 
accompaniment of work, while destruction of tissue took 
place chiefly during rest. In this work consciousness is 
regarded as an epiphenomenon which in no way interferes 
with biological determinism. The author assumes the 
existence of a molecular consciousness which arises from 
atomic consciousness, and, by a process of fusion, passes 
hOn tage, VOL. 55] 
into plastidular consciousness, or that of the lowest living 
organic element. The consciousness of man or of the 
higher animals is regarded as the sum of the individual 
consciousness of the neurons of which the nervous system 
1s composed, and is dependent on the arrangement of the 
neurons. Starting from these assumptions, the author 
adopts the views of Duval and Ramon y Cayal, and ex- 
| plains such modifications of consciousness as sleep and 
| altered personality by differences in the relations of the 
neurons to one another. 
Report of Observations of Injurious Insects and Common 
Farm Pests during the year 1896, with Methods of 
Prevention and Remedy. By Eleanor A. Ormerod, 
F.E.S., F.R.Met.Soc., &c. Pp. 160. (London: Simpkin, 
Marshall, Hamilton, Kent, and Co. Ltd., 1897.) 
Miss ORMEROD’S reports are so well known among 
economic entomologists, that it is almost unnecessary to 
state that the latest of her valuable volumes (the twentieth) 
furnishes interesting and serviceable information upon 
the insect pests prominent in 1896. One of the worst 
insect attacks of the season was that of various kinds of 
caterpillars to leafage of forest and fruit trees. In 
various localities in Kent, Sussex, Surrey, Hampshire, 
and other counties, in May last, hundreds of trees were 
stripped of their leaves by caterpillars of the Oak-leaf 
Roller Moth, the Mottled Umber Moth, and of the 
Winter Moth. Miss Ormerod describes the life-histories 
of these pests, and the measures used to prevent the 
attacks. A very important account is given of the 
occurrence of “Onion-sickness,” arising from the presence 
in the bulbs, of the Stem Eelworm, known in this country 
as causing “ Tulip-rot” in Oat-plants, and “ Stem-sick- 
ness” in Clover. Among other insect pests described, 
with the means of exterminating them, are the Codlin 
Moth—one of the yearly troubles of the fruit-grower ; 
Beet Carrion Beetle, which has taken to feed on potato 
leafage ; White Cabbage Butterflies, German Cockroach, 
Common Earwig, Caddis Worms, Pear and Cherry 
Sawfly, and Surface Caterpillars. 
Miss Ormerod pays an affectionate tribute to the 
memory of her sister, whose death last August deprived 
her of a constant companion ever ready to assist her in 
the investigation and illustration of the life-histories of 
injurious insects. 
Grasses of North America. By W. J. Beal. 
Pp. 706. (New York: H.-Holt and Co., 1896.) 
THE first volume of Dr. Beal’s “Grasses of North 
America” was published in 1887, and was a work in- 
tended more especially for farmers and students, com- 
prising chapters on the physiology, composition, selection, 
improving, and cultivation of grasses and clovers. The 
present volume may be regarded as a separate work. It 
is confined to the Graminez, and constitutes a mono- 
graph of the North American grasses, native and intro- 
duced, with an illustration of each genus. Some idea of 
the magnitude of the task may be gathered from the fact 
that the native grasses alone of North America number 
about 1275 species, included in about 140 genera ; while 
in Europe there are only 47 genera and 570 species. 
The author brings to his subject a wide practical know- 
ledge, which will make the work of great value to 
systematic botanists. There is a useful chapter on the 
geographical distribution of North American grasses, 
and a copious bibliography is appended. 
The Culture of Vegetables for Prizes, Pleasure, and 
Profit. By E. Kemp Toogood, F.R.H.S. Pp. 127. 
(Ulverston : William Holmes, 1897). 
CorraGE gardeners will find in this little volume many 
useful hints on varieties of alimentary plants, soil-work- 
ing, rotation, manures, garden p2sts, and vegetable cul- 
ture generally. The book is a trustworthy and practical 
guide, dealing with methods alone, little attentioa being 
Vol. il 
\ given to the principles underlying them. 
