606 
NATURE 
[AUGUST 13, #914 
together with all the ternary alloys and systems of 
a higher order. The second volume now under 
notice deals almost exclusively with the iron- 
carbon system. 
Dr. Guertler has thus undertaken an immense 
task, and has shown marvellous industry in the 
sifting and presentation of so large a mass of 
material. The published data referring to each 
system have been critically reviewed, tempera- 
tures have been reduced as far as possible to a 
uniform scale, and the equilibrium diagrams in 
which the author embodies his conclusions repre- | 
sent a large amount of patient labour and acute 
criticism. It is impossible, however, to escape a 
doubt whether so great an undertaking is justified 
in the present state of the science. It is well 
known that very many of the published investiga- 
tions on this subject have been carried out with 
rough experimental methods and impure 
materials, and can only be regarded at best as 
preliminary surveys. Even the author’s critical 
examination of the data cannot bring conclusive 
results out of such material. At the present time 
many of the binary systems are undergoing re- 
examination by competent investigators, often 
with surprising results, and for some years to 
come any systematic account of metallic alloys 
must be regarded as merely provisional. Such a 
work as the present is inevitably out of date before 
its publication is complete. This being admitted, 
however, all metallographers must be deeply 
grateful to Dr. Guertler, who has provided them, 
in a compact form, with a carefully sifted collec- 
tion of experimental data, otherwise difficult of 
access, enriched with comments of a thoroughly 
sound and practical character. 
It is an astonishing fact that six hundred pages 
are required to give an account of the equilibria 
in a single binary system, that of iron and carbon. 
The volume devoted to these alloys leaves out of 
consideration the whole field of the technical treat- 
ment of iron and steel, of their physical and 
mechanical properties, and of the influence of 
other elements on the system. Probably no better 
guide than the author could be found through the 
controversial mazes of this part of the subject, 
and his conclusions are to be received with all 
respect. The recent revolutionary proposals of 
Wittorf and others are subjected to a searching 
analysis, leading to the conclusion that cementite, 
FesC, has a range of stability above 1700°, 
graphite being the stable solid phase between 
1700° and 1360°, whilst the existence of a further 
carbide, FesC, with a small range of stability, is 
regarded as probable. The thorny subject of the 
nature of martensite and troostite receives very 
cult to find two metallographers who are in com- 
plete agreement, and the author’s views are not 
likely to escape criticism. Ingenious diagrams, 
sometimes having the curves corresponding with 
metastable equilibria printed in colours, are used 
in this volume, which is indispensable to all who 
are seriously interested in the constitution of cast- 
iron and steel. 
The book is admirably printed. In the course 
of constant use few misprints have been detected, 
with the exception of proper names, which are 
rather frequentiy mis-spelled. References are only 
given by author’s name and year of publication, 
the details having to be sought in a bibliography, 
which is to appear on the completion of the work. 
In the first volume it would have been of advan- 
tage to provide a larger number of photo-micro- 
graphs in some sections, but those which are in- 
cluded, most of which are fairly familiar, are well 
reproduced. The second volume is profusely 
illustrated. C: Hi. Desens 
ZOOLOGY, EMBRYOLOGY?) AND 
HEREDITY. 
(1) Handbuch fiir Biologische Uebungen. By Prof. 
P. Réseler and H. Lamprecht. Zoologischer 
Teil. Pp. xii+574. (Berlin: Julius Springer, 
1914.) Price 27 marks. 
(2) Konstitution und Vererbung in ihren Begieh- 
ungen sur Pathologie. By Prof. F. Martius. 
Pp. viiit+258. (Berlin: Julius Springer, 1914.) 
Price 12 marks. 
(3) Leitfaden fiir das Embryologische Praktikum, 
und Grundriss der Entwicklungslehre des 
Menschen und Wirbeltiere. By Prof. A. 
Oppel. Pp. vii+ 313. (Jena: Gustav Fischer, 
1914.) Price 10 marks. 
(4) Studies in Cancer and Allied Subjects. Vol. 
iv., Contributions to the Anatomy and Develop- 
ment of the Salivary Glands in the Mammalia. 
(Conducted under the George Crocker Special 
Research Fund at Columbia University.) Pp. 
v+364+plates. (New York: Columbia Uni- 
versity Press, 1913.) Price 5 dollars net. 
(1) HIS handbook appears to be meant 
specially as a guide to teachers who 
have to conduct courses of practical instruction in 
zoology in higher schools and colleges, but who- 
ever works conscientiously through it, whether a 
prospective school teacher or not, will have gone 
through an excellent course in practical zoology 
on the “type” system. He will have given him- 
self a practical training of a much sounder and 
more extensive kind than is, we fear, commonly 
attempted by those who have to conduct such 
courses in the schools of this country. We fancy 
d er 
full treatment, but on this point it would be diffi- | that if our science masters had to work through 
WO) "23275 VielBOs) 
