224 Notices respecting New Books. 
view supported by Mr. Muir is that put forward more especially 
by Lossen; and from the arguments adduced this seems to be the 
most philosophical in the present state of our knowledge. 
The section on Isomerism includes an account of Groth’s erys- 
tallographical researches on the derivatives of benzene, and gives 
in detail the more important inexplicable phenomena of isomerism 
presented by hydrobenzoin, dulcitol, the lactic and tartaric acids, &c., 
the discussion of which adds considerably to the interest of this 
portion of the book. Here also Lehmann’s important researches 
on physical isomerism have a prominent place. 
The Periodic Law is treated in a separate chapter, and more 
fully, we believe, than in any other English text-book. It will 
thus be of valuable assistance to those who are unable to consult 
the original memoirs on this subject. Scarcely sufficient credit, 
however, is given to Newlands, who, in the publication of his ‘ Law 
of Octaves,’ was certainly the first to draw attention to the periodic 
connection between the atomic weights and the properties of the 
elements. The periodic relation between the atomic weights and 
the heats of formation of the elements with chlorine, bromine, and 
iodine, which was first pointed out by the writer of this review in 
a paper published in the ‘ Proceedings’ of the Royal Society, and 
also at greater length in another paper in the Chemiker Zeitung, 
is erroneously ascribed by Mr. Muir to Laurie, whose paper was 
only published by the Royal Society of Edinburgh some years sub- 
sequently. 
The section dealing with Thermo-chemistry will, we think, be of 
very great service to teachers, as there are but few English text- 
books which even refer to this subject. The value of this section 
is also greatly enhanced by the numerous, varied, and well-chosen 
examples which are given of problems dealing with heat-changes 
produced by chemical action. 
In Book IL., under the head of Chemical Kinetics are included 
facts and principles which chiefly relate to chemical action as 
opposed to those which refer more especially to chemical composi- 
tion. It is evident, as the author states, that this division can 
only be carried out in the broadest way, but it is nevertheless a 
very convenient and useful division for working purposes. The 
same facts, for a complete knowledge of their bearings, must be 
studied from both a Statical and Kinetical point of view. 
Under Kinetics we have a chapter on Dissociation, followed by 
one on Chemical Change, wherein are discussed at length the theories 
of Williamson, Pfaundler, Horstman, and Gibbs; and an account 
is also given of the work of Gladstone, Harcourt, and Menschutkin 
on this subject. In a chapter on Chemical Affinity much stress is 
laid on the dynamical hypothesis of Guldberg and Waage, which 
is shown to be almost independent of any molecular theory of the 
structure of matter; whilst, as extended by Ostwald, “it forms a 
bridge connecting the investigation of the chemical properties of 
molecules with that of the action of the forces which come into 
