556 
NATURE 
[JuLy 30, 1914 
ing the advent of a new era in consequence of | and theories of chemistry in historical sequence, 
the appearance of the first volume of the 
Zeitschrift fiir physikalische Chemie. This year 
affords, no doubt, an excellent point of departure ; 
but to qualify it as “the beginning of the transi- 
tion from a system into a science of chemistry ” 
(p. 17) is surely incorrect. Granted the profound 
development which has taken place in the direction 
of physical chemistry during this period, it would 
be a gross misconception of the word “science ”’ 
to deny the term to chemistry during the greater 
part of last century. If, as the author truly re- 
marks, it is the generalisations or laws which 
transform chemistry from a system into a science, 
he assuredly contradicts his assertion when, for 
example, he develops the laws connected with the 
history of mass action. But, apart from this, 
there are many other statements which are equally 
inaccurate. One would scarcely venture to 
describe Stas’s method as “crude” (p. 3), or to 
regard Prouts’s hypothesis as correlating atomic 
weights with the physical and chemical properties 
of the elements (p. 4), or to represent Kekulé’s 
benzene formula as a triangle with the carbon 
and hydrogen groups occupying the corners and 
middle points of the sides (p. 12), or to state that 
Le Bel’s advance on Pasteur’s theory consisted 
in showing “‘that optical activity is the expression 
of asymmetry, but that this asymmetry is of the 
chemical molecule”; for it was precisely what 
Pasteur did suggest, as anyone who has read his 
lectures on molecular asymmetry can scarcely fail 
to remember. 
Sufficient has been stated to show a certain 
amount of carelessness in the handling of his- 
torical details; and, in regard to the elucidation 
of complex problems, we doubt whether any 
student who was not already familiar with the 
subject would follow the account of, for example, 
Berthollet’s contribution to the law of mass action, 
or Le Chatelier’s rule (p. 80), or the explanation 
of osmotic pressure (p. 90). The expressions “ to 
arrest attention to the importance of,” “the 
method was to cut and try to see what result 
was obtained,” are not exactly elegant English, 
and the frequent repetition of the same word, such 
as “generalisation,” 
in seven pages, point to hurried and slovenly com- 
pilation. The book is, on the whole, disappoint- 
ing. 
(3) The first edition of Sir William Tilden’s 
book on the progress of scientific chemistry is too 
well known and appreciated for any special recom- 
mendation of the new edition, which merely bring's 
the subject up-to-date, to be necessary. For those 
who may not have seen or read the earlier volume, 
it may be stated that it sets forth the main facts 
NO. 2335, VOL. 93] 
and traces the development of the various branches 
of the science down to the present time. The 
subjects are not discussed with any great detail 
or elaboration, but the style is fresh and attrac- 
tive, and the explanations clear and incisive, so 
that the merest tyro in chemistry can easily follow 
all that he reads. With one notable exception 
it would be difficult to find anyone at the present 
day whose long association with chemistry both 
as teacher and investigator, and whose personal 
contact with many of the great chemists of this 
and the latter part of last century, could better fit 
him for the task of a historian, and the volume will 
furnish not the least valuable of the many con- 
tributions to chemistry of its distinguished author. 
J; Ba: 
OUR BOOKSHELF. 
The Makers of Modern Agriculture. By Dr. W. 
Macdonald. Pp. 82. (London: Macmillan 
and Co., Ltd, 19r4.)) Price 2s. Ga. met 
In this little book Dr. Macdonald has given a 
very pleasant and readable account of five of the 
makers of modern agriculture, viz., Jethro Tull, 
Coke of Norfolk, Arthur Young, John Sinclair, 
and Cyrus H. McCormick. He has carefully 
examined the best biographies available, and has 
given a summary of the lives and works of his 
subjects, which cannot fail to be of wide interest 
to all concerned in the development of agricultural 
science. If we have a fault to find, it is that the 
title is too comprehensive: Lawes and Gilbert 
are not mentioned, yet they must surely stand 
among the makers of modern agriculture, for it 
was they who worked out the application of arti- 
ficial manures to agricultural practice. Three of 
the five are Englishmen, one is Scotch, and one 
American. Tull and Coke are in some ways the 
most interesting of the five. 
Tull was born at Basildon in Berkshire in 1674, 
and did his best work in the same county. His 
claim to fame is that he invented the method of 
| drilling seed, which has now displaced the older 
method of broadcasting or dibbling. He was 
thus able to secure an opportunity for cultivating 
land even while the crop was growing. In con- 
' sequence, bare fallow could be dispensed with, 
which occurs twenty times | 
and the land could be utilised throughout the 
whole of the rotation. The principles that he laid 
down are wonderfully accurate, while his methods 
have changed only in detail and not in essentials. 
Coke of Norfolk is well known for his remark- 
able work in the development of light, sandy soils. 
It is unfortunate that no satisfactory account of 
his agricultural experiments has yet been pub- 
lished, and one can only hope that this oversight 
on the part of agricultural writers will soon be 
remedied. His experiments at any rate were well 
known in his own day, and the practices he intro- 
duced have been widely followed ever since. 
