Notices respecting New Books. 223 
problems are worked out and made capable of presentation in a 
sinple and concise manner. 
The work is divided into two parts. In the first, which in the 
main deals with Chemical Statics, we have a statement and discus- 
sion of the Atomic and Molecular theory, and its application to such 
subjects as isomerism, allotropy, nascent action, and classification. 
Tn this part there is also an account of the application of physical 
methods to the solution of chemical problems. The second part 
treats with such subjects as may be conveniently considered under 
Chemical Kinetics, as dissociation, chemical change, and equilibrium, 
affinity, and the relations between chemical action and the distri- 
bution of the energy of the changing system. 
The chapter on Atoms and Molecules is remarkably well written, 
and gives a clear account of the growth of the views at present 
held by chemists. In that portion dealing with the molecular 
weights of solids, the author seems to have overlooked the import- 
ant work of Prof. Louis Henry on the Polymerization of the 
Oxides, in which this subject is treated in a very masterly manner 
and most cogent arguments adduced in favour of the view that the 
molecular weights of solids are much higher than is represented 
by the simple formule usually assigned to them. Our own re- 
searches on the colour of chemical compounds, so far as they go, 
are in favour of Prof. Henry’s views. 
After an account of the service which vapour-density, specific 
heat, and isomorphism render in the determination of atomic 
weights, the nature of the methods based on purely chemical evi- 
dence is next described ; and the chapter finally concludes with an 
exceedingly good and useful table giving a summary of the most 
important facts concerning the atomic weights of the elements. 
This table we consider to be a marked and very valuable feature 
in the book; for we fully agree with the author that “it is well 
that the student should have placed before him a synopsis of the 
evidence on which these all-important numbers are based.” The 
table is also rendered additionally useful by copious references to 
the original memoirs. 
Chapter II gives a good résumé of the more important facts 
bearing on “ nascent action,” an expression which the author con- 
siders to have been “at once helpful and harmful to the progress 
of Chemistry. By classing under a common name many pheno- 
mena that might otherwise have been lost in the mass of facts with 
which the science has to deal, the expression has done good service; 
but in so far as its use has tended to prevent investigat?on—for it 
is always easier to say of any,unusual reactions, These are cases of 
nascent action, than to examine carefully into their cause and con- 
ditions—the use of the expression has been unfavourable to the best 
interests of chemical science.” The sections of this chapter treating 
of equivalency, allotropy, and isomerism are well worthy of carerul 
perusal, and will undoubtedly serve a good purpose in giving 
teachers of Chemistry a clearer and more concise idea of the meaning 
which ought to be attached to the vexed term “atomicity.” The 
