NATURE 
601 
PAURSDAY.) APR 25; 
THE DEVELOPMENT OF 
REE ORV: 
A History of Chemical Theory and Laws. By M. M. 
Pattison Muir. Pp. (New York: John 
Wiley and Sons; London: Chapman and Hall, 
Ltd., 1907.) Price 17s. net. 
HIS _ book, the author remarks in several 
places, is not intended as a history of chemistry, 
but as an account of the development of chemical 
theory, an account of attempts “‘to describe, to set 
in due order, and to connect the changes of composi- 
tion and the changes of properties which 
simultaneously in systems of homogeneous  sub- 
stances, and the conditions under which these changes 
proceed.” Or, as the author again expresses his 
intention, it is ‘‘to trace the forms which the two 
fundamental inquiries of chemistry have presented 
at different periods, to describe some of the methods 
which have been used to find answers to these 
inquiries, and to set forth the general results of the 
application of these methods.’’ The two fundamental 
inquiries relate to the questions, ‘‘What is a 
chemically distinct substance? ’? and ‘‘ What happens 
when chemically distinct substances interact? ”’ 
These questions are treated historically. In answer 
to the first, the author deals with the ‘‘ recognition 
of homogeneous substances, and the description of 
chemical changes as the interactions of those sub- 
stances; the marks of elements and compounds; the 
laws of chemical combination, the atomic hypothesis, 
the molecular and atomic theory; the composition of 
homogeneous substances—allotropy; elements which 
do not react; and chemical nomenclature and classifi- 
cation.’’ In answer to the second question, an account 
is given of ‘‘ the classification of homogeneous sub- 
stances; acids, bases and salts; radicals, types, 
dualism, the unitary hypothesis; chemical equi- 
valency; isomerism and constitutional formule; the 
hypothesis of ionisation; the periodic law; the con- 
ditions and laws of chemical change; chemical 
affinity; chemical equilibrium; and lastly, the elucid- 
ation of chemical reactions by measurements 
physical properties.”’ 
In pursuit of this plan, the autMor treats first of 
ancient conceptions up to the year 1780; Lavoisier’s 
systematisation is next considered; then follows a 
historical sketch of the doctrine of atoms, leading to 
the differentiation of the atom and the molecule. 
An account of more modern work is here introduced, 
in which the van ‘t Hoff-Arrhenius extension of 
gaseous laws to dilute solutions is gone into in some 
detail; and the conception of a molecule having been 
developed, allotropy is treated of as due to molecular 
complexity or arrangement. The inert gases of the 
argon group are next mentioned, and in an appendix 
chemical nomenclature and notation. 
In the second part of his book Mr. Muir discusses 
the classification of substances into acids, bases, and 
NO. 1956, VOL. 75 | 
CHEMICAL 
XX + 555: 
as 
occur 
of 
the 
salts; he describes the development of the theory of 
types and radicals, leading to chemical equivalency ; 
and he extends these conceptions to cover the field 
| of molecular structure, dealing with isomerism and 
constitutional formule. 
The next section treats of ionisation; then follows 
In 
a third section the subiects considered are chemical 
affinity; chemical equilibrium; the relations between 
physical of and their 
as exemplified by their optical 
properties and their thermal behaviour. 
a short account of the periodic classification. 
properties substances 
chemical reactions, 
These subjects are illustrated by suitable extracts 
from the works of the investigators who forwarded 
the Quotations from Boyle, Priestley, and 
Lavoisier give an idea of these authors’ styles, and 
render clear the subject-matter which is under dis- 
cussion. 
theories. 
To give an instance :— 
“To-day it is possible to recognise a certain re- 
semblance between the saying of Stephanus of 
Alexandria (about 620), ‘it is necessary to deprive 
matter of its properties in order to draw out its 
soul,’ and the statement of Lavoisier (1789) that the 
object of chemistry is ‘to decompose the different 
natural bodies... and to examine separately the 
different substances which enter into their combin- 
ation.’ The first statement rested on a sweeping and 
superficial glance over an intricate maze of occur- 
rences, and it produced little accurate knowledge. 
The second statement was a result of the penetrating 
study of a few detached events; it was a translation 
of the first statement into expressions which. could be 
directly applied to a vast number of particular pheno- 
mena, and in a few years it produced a science.” 
So far as possible the authors alluded to tell their 
own stories, and the reader’s attention is directed by 
Mr. Muir to the salient points in their conclusions. 
It is better, on the whole, to treat chemical science 
as Mr. Muir has treated it, in following out the 
history of the development of each idea, so far as 
that is possible, than to attempt a chronological 
history; the one is the philosophy of history, the 
other is apt to be overburdened with unconnected 
detail. A third plan is the biographical one; to select 
certain chemists who have contributed to the advance- 
ment of their science, and to show, by an account of 
the life-work of each, how far discovery has been 
furthered. There are difficulties in all methods of 
treatment; probably the one chosen by Mr. Muir 
tends most towards lucidity. 
In his preface, Mr. Muir writes :— 
“Some may say I have omitted much that is 
important, others may think I have included not a 
little that is trivial. In such matters a writer must 
use his own judgment, after he has trained it to the 
best of his ability.”’ 
And at the beginning of the chapter on chemical 
equilibrium, he says :— 
““He who would describe in detail the historical 
development of chemical equilibrium must be a 
chemist, a physicist, and a mathematician; he must 
be a man of great learning, vast audacity, and much 
literary ability.”’ 
DD 
