.* 
% 

(4) Colloid Chemistry of the Proteins. 
. 
. Juve 2, 1923] 
NATURE 
733 

_ Physico-Chemical Themes. 
(1) Catalysis with special reference to Newer Theories 
of Chemical Action: A General Discussion held by 
the Faraday Society. (Reprinted from the Trans- 
actions of the Faraday Society, Vol. 17, Part 3, 
May.) Pp. 545-675. (London: The Faraday Society, 
1922.) 9s. net. 
(2) Some Physico-Chemical Themes. By Prof. A. W. 
Stewart. Pp. xii+419. (London: Longmans, 
Green and Co., 1922.) 21S. net. 
(3) The Theory of Allotropy. By Prof. A. Smits. 
Translated from the German with the Author’s 
sanction, by Dr. J. Smeath Thomas. (Text-books 
of Physical Chemistry.) Pp. xiii+397. (London: 
Longmans, Green and Co., 1922.) 21s. net. 
By Prof. Dr. 
W. Pauli. Translated by P. C. L. Thorne. Part I. 
Pp. xi+140. (London: J. and A. Churchill, 1922.) 
8s. 6d. net. 
(5) Laboratory Manual of Colloid Chemistry. By Prof. 
H. N. Holmes. Pp. xii+127. (New York: J. 
Wiley and Sons, Inc. ; London: Chapman and Hall, 
Ltd., 1922.) ros. net. 
(6) Atomic Form: with Special Reference to the Con- 
figuration of the Carbon Atom. By E. E. Price. Pp. 
_ iv+140+Vvill. (London: Longmans, Green and 
Co., 1922.) 5s. net. 
(x) HE Faraday Society’s general discussion on 
“Catalysis with Special Reference to 
Newer Theories of Chemical Action” was apparently 
arranged in view of the simultaneous presence in 
_ England of Prof. Perrin, Dr. Irving Langmuir, and 
_ Prof. Arrhenius. 
_ dealt with the radiation theory of chemical action 
. and the second session with heterogeneous reactions, 
The first session of the discussion 
and these form Parts I. and II. of the report. The 
discussion on the radiation theory (which postulates 
that chemical action is due to radiation and that its 
velocity is proportional to the prevailing radiation- 
density) was characterised by two dramatic incidents, 
Prof. Lindemann pointed out that,-if the original 
form of the radiation theory were correct, the inversion 
of cane sugar must be determined by the density of 
radiation of wave-length t-o5 4; on this basis, the 
inversion should proceed 50 billion (5x 101* times 
more rapidly in sunlight than in the dark), whereas 
actually the acceleration is almost negligible. Follow- 
ing up this criticism, Dr. Langmuir said that the 

radiation theory “has all the characteristics of the 
typical unsuccessful hypothesis,” since it has been 
made progressively more complicated, as successive 
attempts at verification have failed. Probably no 
theory has ever been put forward in which discrepancies 
NO. 2796, VOL. 111] 
of such magnitude have appeared, and it is at least 
a sign of courageous optimism that the authors should 
still hope to bring it into line with facts. 
The discussion on heterogeneous reactions was 
opened by a paper in which Dr. Langmuir discussed 
the function of the solid surface, with special reference 
to the occlusion of oxygen on the surface of a tungsten 
filament. This takes place at a temperature of 1500° K, 
or more, even when the pressure is so low as 107 
atmospheres, or when hydrogen, ammonia, or methane 
is present, as well as oxygen, showing that the film 
of occluded oxygen is extremely tenacious. It was 
Suggested that the stable film is of monomolecular 
thickness, and that the film can only be dissipated 
in the form of the oxide WO,. In the same way the 
tenacity with which a trace of carbon monoxide will 
cling to the surface of platinum, acting as a powerful 
poison as regards its catalytic activity towards hydrogen 
and oxygen, is attributed to the formation of a mono- 
molecular film of carbonic oxide united chemically 
with the molecules of platinum. Carbon dioxide 
does not behave in this way, and does not act as a 
poison to the catalyst. On the other hand, the normal 
action of the catalyst in the presence of oxygen is 
attributed to the formation of a film of chemically 
bound oxygen of higher activity than the free gas. 
Experimental work on the catalytic action of 
platinum in the oxidation of carbon monoxide and of 
hydrogen formed the subject of the second paper ; 
and the discussion which followed is reported in full, 
together with a number of written communications 
on the same subject. 
(2) Prof. Stewart has added another to the series 
of books, in which he has summarised, mainly perhaps 
for the benefit of the candidate for a degree in honours, 
some of the results of recent chemical research. The 
method of handling the material in such a volume is 
fairly familiar, and criticism may be limited to the 
question as to whether the work has been well done. 
On the whole, the answer may be given in the affirma- 
tive, but in more than one instance the reader who is 
familiar with current research will feel disappointed, 
because some of the sections appear to have been 
written so long ago that they are out of sympathy 
with current thought, even although later work may 
be included either in the same or some other part of 
the volume. Thus to many it would appear futile 
to discuss the theory of the colloidal state without 
including any reference to the work of McBain on 
colloidal electrolytes, which has now been going on 
for something like ten years ; again it is merely tedious 
to read through a discussion as to whether hydrogen 
should be placed in Group 1 or Group 8 of Mendeléeff’s 
classification, when modern theory makes it quite 
Wat 
