ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
95 
Coalescence in Steels. — A. Portevin and Y. Bernard {Iron and 
Steel Inst. Meeting , September, 1921). The authors point out that 
coalescence between similar phases of a system is a natural phenomenon 
which appears to be closely connected with the general tendency for the 
energy of such a system to become a minimum. The results of this 
habit are depicted in a really beautiful series of photomicrographs, 
showing characteristic structures of coalescence under different magnifi- 
cations and with various etching reagents. F. I. G-. R. 
Mechanical Properties of Steels at High Temperatures.— E. L. 
Dupuy ( Iron and Steel Inst. Meeting , September, 1921). The object 
of this research is the determination of the mechanical properties of 
steels in respect of their carbon percentages at all temperatures between 
the normal and incipient fusion. Both rolled and cast material were 
used for studying effect of grain-size and orientation. The author 
makes the interesting observation that Armco Iron (carbon less than 
0*02 p.c.) is incapable of forging or rolling between 850° and 990° C. 
Several plates of photomicrographs are included. A particularly 
valuable feature is the use of a solid (i.e three-dimensional) model 
illustrating the relationship existing in such samples between tempera- 
ture, carbon content, and reduction of area. Such models, representing 
states of equilibria between the constituents of ternary alloys, have been 
used in this country by Prof. Desch and others, but the extension of 
the system to the case of mechanical variables is interesting and worthy 
of attention ; more especially if the model is used in connexion with 
the study of the microphotographs given in the paper. The author 
gives the results of his investigations in terms of well-defined “ regions ” 
of the iron-carbon equilibrium diagram. F. I. G. R. 
Damascene Steel.— N*T. Belaiew {Iron and Steel Inst . Meeting , 
September, 1921). The author considers that there is a marked 
analogy between high-speed and damascene steels, and proceeds to a 
fairly detailed comparison. Damascene steel belongs to the hyper- 
eutectoid variety— in many samples the carbon content is about 1*5 p.c. 
Accompanying the paper is a remarkable photograph (under high 
magnification) depicting the structure of an Indian blade, showing 
globules of spheroidized cementite embedded in a sorbitic matrix. 
F. I. G. R. 
Magnetic Separation of the Lines of Iron, Nickel and Zinc in 
Different Fields. - K. Yamada {Journ. Coll. Sd. Tokyo , 1921, 41, 
Art. 7). The object of rhe investigation was to determine whether the 
separations of Fe and Ni were proportional to the fields applied. 
Photographs show separations of their outer two components proportional 
to the fields applied. In the case of zinc (A. : 3345 ■ 13) the separation 
is a linear function of the field. F. I. G. R. 
Magnetic Separations of Iron Lines in Different Fields. — 
Y. Takahashi {Journ. Coll. Sci. Tokyo , 1921, 41, Art. 8). Many 
sharp lines give separations proportional to the magnetic field as if 
