NOVEMBER 13, 1913] 
NATURE 
497 
III 
produced by polishing were not of molecular thinness, 
but really very deep. Unlike the author, he con- 
sidered the microscopical evidence of a mobile phase 
in the interior of a strained metal conclusive. 
Dr. C. H. Desch considered it necessary to dis- 
tinguish between the hypothesis of amorphous phase 
in strained metal, due to Dr. Beilby, and that of an 
intercrystalline cement in unstrained metal, developed 
by Dr. Rosenhain. The first was now fully estab- 
lished; the second, although highly ingenious, was 
yet unproved. Most of the facts could be explained 
by the surface tension of the crystal grains. 
Dr. Rosenhain, in reply, said that iron, unlike 
calcite, would not give a layer of amorphous material 
without the use of a powder. He could not agree 
that there would be any surface tension at the boun- 
daries of crystals in contact. 
In a paper by F. E. E. Lamplough and J. T. Scott 
it was stated that the ‘‘halos”’ sometimes seen around 
the crystallites in alloys containing a eutectic are not 
due to undercooling, but to segregation. They appear 
more readily when the alloy is slowly cooled, and 
their formation still occurs when undercooling is pre- 
vented by inoculation. By quenching experiments it 
is shown that the two constituents of aeutectic crystal- 
lise simultaneously, not alternately. 
Prof. T. Turner’s paper on the volatility of metals, 
especially under reduced pressure, was concerned with 
a subject in which there are considerable possibilities 
of future practical application. Distillation in vacuo 
is specially suitable for easily oxidisable metals such 
as sodium, potassium, cadmium, and zinc. Quantita- 
tive separations of the constituents of some alloys can 
readily be effected at suitable temperatures in vacuo. 
A general description of the work was given with par- 
ticular reference to the influence of the pressure on 
the rate of volatilisation. 
The structural changes brought about in certain 
alloys by annealing formed the subject of a paper by 
Mr. O. F. Hudson, which had reference mainly to 
those alloys which consist of a solid solution. On 
annealing, the cored structure characteristic of the 
cast alloy disappears and the crystals become quite 
uniform. Structurally the alloy does not now differ 
from a pure metal. Alloys which have been worked 
before annealing practically became recrystallised 
during the process. In the case of alloys consisting 
of crystals of two or more kinds, the chief effect of 
annealing is to promote equilibrium between the two 
phases present. Prolonged annealing is required to 
attain complete phase and structural equilibrium. 
The paper gave a valuable summary of the existing 
knowledge on the subject. 
In a paper on diffusion in solid solutions, Dr. C. H. 
Desch alluded to the fact that since his report to the 
Dundee meeting of the association, Bruni and 
Meneghini have succeeded in demonstrating the 
occurrence of diffusion in a clear, crystalline solid in 
the case of sodium and potassium chlorides. A mix- 
ture of these two salts, heated at 500° or 600°, yields 
a homogeneous solid solution, the formation of which 
is recognised by determining the heat of solution in 
water, which differs from that of a mechanical mix- 
ture. The author’s further experiments with metallic 
alloys show that a sharp boundary is characteristic 
of diffusion in solids when a chemical compound is 
formed. An abrupt discontinuity of composition is 
also observed when one component is removed by 
solution, as in the dezincification of alloys of copper 
and zinc. 
Mr. E. Vanstone described the methods and results 
of determinations of the electrical conductivity of 
sodium amalgams when in the solid state. 
The work described by Dr. A. Holt in a paper 
entitled ““The Solubility of Gases in Metals’’ had 
NO. 2298. voL. a2] 
reference mainly to the solubility of hydrogen. in 
palladium, but there seems distinct evidence that the 
phenomena are not peculiar to this case, but occur 
also with other metals and gases. 
Rapid solution of gas appears only to take place 
when the metal is in an amorphous condition. The 
metal may be wholly amorphous, as in the case of 
palladium black, orit may havean amorphous surface 
associated with amorphous films round the crystals 
of the otherwise holocrystalline material. The rate 
of solution appears to depend on the amount of 
amorphous metal present, hence when the amorphous 
and crystalline phases are in physical contact, the 
metastable amorphous phase tends to crystallise, and 
so causes a falling off in the rate of solution. When, 
however, the amorphous phase alone is present, the 
rate of change is so excessively slow that the rate of 
solution appears to be a constant, even after a long 
period of years. 
The activity can be increased up to a maximum 
value by repeated saturation and removal of gas 
from the metal. According to Beilby, ‘‘the gas 
molecules as they find their way among the metal 
molecules of the solid are quite capable of producing 
sufficient movement to arrest crystallisation, or even 
to flow the crystals which are already formed into the 
amorphous variety,” and this would explain the above- 
mentioned increase in activity. 
Since, however, all forms of the metal appear 
eventually to dissolve almost the same volumes of 
gas, it must be concluded that when the metal is 
mainly crystalline, the amorphous phase functions as 
a vehicle for the transference of gas, for some 
amorphous metal is always present in physical contact 
with the crystalline phase. 
Dr. R. E. Slade and Mr. G. I. Higson contributed 
two papers. The first, on the equilibria of reduction 
of oxides by carbon, described the methods followed 
to determine the equilibrium temperature and pres- 
sure of carbon monoxide for vanadium, tantalum, 
chromium, tin. The second described the determina- 
tion in a similar manner of the dissociation pressures 
and temperatures of the nitrides of vanadium, 
tantalum, and boron. 
Mr. F. D. Farrow gave a concise summary of the 
recent work on the melting points and dissociation 
pressures of the system copper oxygen, the data being 
collected to form temperature-composition and tem- 
perature-pressure diagrams. The influence of traces 
of impurities on the properties of copper was surveyed 
by Mr. F. Johnson, who urged the importance of 
metallurgical testing and analysis and the use of 
the microscope in studying the commercial brands of 
crude copper for practical use. 
UNIVERSITY AND EDUCATIONAL 
INTELLIGENCE. 
CaMBRIDGE.—It is proposed to confer the degree of 
Master of Arts, honoris causd, upon Mr. W. Dawson, 
reader in forestry / f 
Dr. A. S. F. Griinbaum, of Gonville and Caius 
College, and Mr. F. R. C. Reed, of Trinity College, 
have been approved by the General Board of Studies 
for the degree of Doctor of Science. 
Mr. F. T. Brooks, of Emmanuel College, is leaving 
England for the Federated Malay States, in order to 
make a report to the Government on the fungoid 
diseases and as to whether anything can be done to 
arrest them. Mr. Brooks has received one year’s 
leave of absence from the University. 
Oxrorp.—It is proposed to raise a memorial to the 
late Dr. Francis Gotch, Waynflete professor of physio- 
logy in the University. The form taken by the 
