76 
t 
that the metal acquires a negative.charge during the | 
catalytic combustion of gases in contact with it (thus 
confirming previous unpublished observations by Bone 
and Makower), which effect is probably antecedent to 
the actual combustion, and primarily due to ‘ occlu- 
sion’’ phenomena; (2) that the metal becomes nega- 
tively charged (0-5 to 1-5 volts) during the occlusion of 
the combustible gas (hydrogen or carbon monoxide), | 
and positively charged (0-8 volt) during the occlusion 
of oxygen; and (3) that such electrical effects are 
probably due to occluded gas which is leaving (rather 
than entering) the surface. The experiments indirectly 
lend support to the view that the well-known electronic 
emission from incandescent solids is probably de- 
pendent upon the occlusion of gas.—J. H. Mackie : 
The diffusion of electrons through a slit.—Dr. A. 
Holt : The rate of solution of hydrogen by palladium. 
The rate of solution of: hydrogen at constant (atmo- 
spheric) pressure by palladium in the form of black, 
thin and thick foil has been examined. The rate 
curves in the case of palladium black are simple and 
of continuous curvature, but for the foil a more or 
less pronounced discontinuity of curvature is always 
observed. The discontinuity is accounted for by con- 
sidering that the gas is dissolved in two different forms 
of the metal, the rate of solution being different in the 
two forms. Palladium black is believed to consist 
almost wholly of one form, and hence gives a simple 
rate curve, whilst the foil (which is mainly crystalline) 
contains both varieties of metal, and so gives two 
rates, the first rate passing into the second when solu- 
tion in both forms becomes equally rapid.—Dr. R. A. 
Houstoun ; The dispersion of a light pulse by a prism. 
A light pulse of a form giving the Wien energy dis- 
tribution is incident on a prism, and expressions are 
derived (1) for the disturbance in the region imme- 
diately behind the prism where the different colours 
overlap; and (2) for the disturbance in the focal plane 
of the telescope. The first expression holds only for a 
particular law of dispersion, but the second is for any 
law of dispersion. They are both in accordance with 
results obtained by Lord Rayleigh by considerations 
oi stationary phase and hydrodynamical analogy, but 
they go further. For example, it is definitely stated 
how the amplitude varies in the front and rear of and 
throughout the train of waves given rise to by the 
pulse in the different parts of the spectrum, 
Geological Society, February 20.—Dr. Aubrey Strahan, 
president, in the chair.—Annual General Meeting.— 
President’s address : As his main subject, the president 
referred to that part of the work of George Darwin 
and Wallace which bore on the history and age of the 
earth, and commented on the vagueness of the 
evidence on which estimates of the rapidity of denuda- 
tion in past times are founded. Before attempting 
estimates of primeval time, it should be shown that 
some degree of precision is attainable in calculating 
the amount of denudation effected in post-Glacial 
times, and the time required to effect it. It is now 
possible to distinguish the features in the landscape 
which are due to post-Glacial erosion. River-gorges, 
dissected plateaus, fans, and deltas of gravel are pre- 
sented for consideration. In some there seems to be 
a possibility of estimating the bulk of the material 
which has been moved, and the rapidity with which 
the transporting agents are working. Fans spread on 
the flat bottoms of valleys by tributary streams, or 
deltas formed in lakes, are of common occurrence. 
In all cases it would be of value to determine a rela- 
tion between three factors, namely, the size of the fan 
or delta, the discharge of the stream, and the char- 
acter of the ground from which the material was 
derived. Dammed-up rivers give opportunities for 
observing the amount of material transported by 
NO? 2316) VOL. 92) 
NATURE 
| 
[Marcu 19, 1914 
rolling. The distances over which rivers are now 
transporting material should be ascertainable by ob- 
serving the composition of recent alluvial deposits. 
Few roll gravel directly into the sea, for the sradients 
in the lower parts of their courses are too low for 
transportation and favour deposition. An investiga- 
tion on English rivers has been proceeding for some 
years, with the object of ascertaining (1) the discharge, 
(2) the suspended and dissolved impurities, (3) the rain- 
fall, (4) the areas of the basins, and (5) the character 
of the rocks. The rivers suitable for the investigation 
are limited to those with a single definite mouth. 
Fen-rivers have a number of outlets, and cannot be 
gauged. The amount of material now being rolled 
by the Exe, for example, is determined from records 
of dredgings. Rainfall is dealt with by the British 
Rainfall Organisation, as also the methods of eliminat- 
ing the error in calculating average rainfall, due to 
the preponderance of rain-gauges in the lower ground. 
It was concluded that, although in this country a 
hydrographic survey may not be essential on the 
ground of utility, yet more systematic observations on 
the work of denudation are within the reach of 
geologists. 
February 25.—Dr. A. Smith Woodward, president, 
in the chair.—Rachel W. McRobert: Acid and inter- 
mediate intrusions and associated ash-necks in the 
neighbourhood of Melrose (Roxburghshire). The age 
usually assigned to the igneous intrusions is a late 
period in the history of the ‘‘ plateau-eruptions” of 
Calciferous Sandstone times. The igneous rocks occur 
as laccolites and sills, as dykes, and in volcanic necks. 
The chief rock-types present in the area are porphyritic 
and non-porphyritic sanidine-trachytes, quartz- 
trachytes, riebeckite-felsites, quartz-porphyries, basalts, 
and volcanic agglomerates. The salient features of 
the suite of rocks described are the high content of 
alkalies, and the presence of soda-bearing minerals 
such as riebeckite, e@girine-augite, primary albite, and 
soda-orthoclase. Nepheline was found to be absent 
from most of the rocks.—A. Vaughan: Correlation of 
Dinantian and Avonian. The results are given of 
applying the time-scale deduced from the South- 
Western Province to the Belgian sequence, and shows 
that the faunal succession is practically the same in 
both provinces. If the midland and northern develop- 
ments of England and Wales are compared with that 
of Belgium, striking identities are. observed. The 
lateral variation of Mid-Avonian lithology is exhibited 
in a diagram. Correlation of the Belgian sequence 
with that of the South-Western Province demonstrates 
that the periods of partial emergence took place con- 
secutively and not simultaneously. The palzonto- 
logical section contains descriptions of several gentes 
that are common in Belgium, but. rare in Britain. 
The facts concerning migration and evolution are 
importants results of extending the area of observa- 
tion. 
Linnean Society, March 5.—Prof. E. -B. Poulton, 
president, in the chair—Miss K. Foot and Miss E. C. 
Strobell: Results of crossing Euschistus variolarius 
and I. servus, with reference to the inheritance of an 
exclusively male character. The specific character is 
a distinct black spot on the genital segment of E. 
variolarius, which is wanting in the female, and 
entirely absent from E. servus. The authors ex- 
plained the methods adopted during five consecutive 
summers, for raising these Hemiptera in captivity. De- 
tailed accounts are given of the history of their speci- 
mens, their crossing, and the results in the F, and F, 
generations. The exclusively male character, the 
genital spot, can be inherited without the aid of the 
Y-chromosome or of the X-chromosome. The genital 
spot does not behave as a Mendelian unit; neither the 
