APRIL 29, 1915] 
NATURE 
249 

was of comparatively little use to the youth who would 
be a workman all his life. On the other hand, he 
considered evening technical instruction excellent to 
give youths possessing ability and determination a, 
means of rising from non-technical to technical em- 
ployment. Prof. E. W. Marchant endorsed what Mr. 
Fleming had said with regard to evening classes, and 
said that it seemed to him a physical impossibility for 
a man engaged in manual or other labour during the 
day time to study effectively if he gets his technical 
education in the evening. On the other hand, Prof. 
Miles Waller, of the Manchester School of Tech- 
nology, said that although day classes were better 
for those who could attend them, as the students 
would be fresher and better able to utilise their facul- 
ties, yet the men who came after their day’s labour 
was over and did really good work three evenings 
a week with home lessons on Saturdays and Sundays 
must possess admirable qualities. Mr. J. Collinge 
referred to the difficulty of training young men 
engaged in central stations, who had not been able 
to afford college training, as owing to the character 
of the work and the hours they had to be employed 
they were largely prevented from regular attendance 
at technical schools, and consequently frequently found 
themselves in a ‘blind alley.” 
SOCIETIES AND ACADEMIES. 
LONDON, 
Royal Society, April 22.—Sir William Crookes, presi- 
dent, in the chair.—Lord Rayleigh ; Deep water waves, 
progressive or stationary, to the third order of approxi- 
mation. The principles of hydrodynamics are applied 
to form the equations ot wave-motion to the 
third order of approximation without restriction 
other than that the motion irrotational and 
in two dimensions. The results are then  ap- 
plied to the progressive wave of permanent 
form, as investigated by Stokes, and to stationary 
waves. It appears that the form of the latter at the 
moment of greatest deviation from mean level is the 
same as that of the permanent progressive wave, but 
that the periods of vibration corresponding to the 
same wave-length are different—Hon, R. J. Strutt: 
A chemically active modification of nitrogen, produced 
by the electric discharge. VI—Dr. C. Chree: The 
difference between the magnetic diurnal variations on 
ordinary and quiet days at Kew Observatory. The 
paper considers the difference between the diurnal 
variations of magnetic force at Kew Observatory on 
quiet days and ordinary days (i.e. all days with the 
exception of those of large disturbance). The data 
employed are from the eleven years 1890-1900. Taking 
mean data for the whole year, the difference in the 
horizontal plane may be regarded as consisting, to a 
first approximation, of a harmonic oscillation of 
twenty-four hour period along a direction inclined 64° 
east of north and of a regularly progressive non- 
cyclic change in a second direction which is perpen- 
dicular to the former. The result, while true of the 
days of the year as a whole, is only imperfectly 
exhibited in most individual months.—F. Horton: The 
effects of different gases on the electron emission from 
glowing solids. An investigation has been made of 
the ionisation produced by a glowing Nernst filament 
when used as a kathode in a discharge tube in the 
presence of various gases of different chemical affinities 
for the material of the filament. It has been found 
that the actual electron emission from the filament is 
independent of the nature of the surrounding gas, at 
least for the gases, air, nitrogen, oxygen, and 
hydrogen, for at low pressures the thermionic currents 
measured under similar conditions in these gases were 
NO. 2374, VOL. 95] 
is 


practically the same. At higher pressures the therm- 
ionic currents differ considerably owing to the effect 
of ionisation by collisions being different in the different 
gases. The increase in the current due to ionisation 
by collisions in hydrogen is much greater than it is in 
air, oxygen, or nitrogen. The experiments were re- 
peated with a Nernst filament covered with lime, and 
it was similarly found that the electron emission from 
lime under these conditions was not increased by 
hydrogen, although earlier experiments have shown 
that lime heated on platinum gives a much larger 
electron emission in hydrogen than it does in air. 
This appears to be caused by the hydrogen increasing 
the emission from the platinum, an effect which has 
been shown by H. A. Wilson to be due to the absorp- 
tion of hydrogen by the metal. Lime and the oxides 
of a Nernst filament do not absorb hydrogen, and the 
electron emission from these substances is therefore 
unaltered by the presence of this gas. That the elec- 
tron emission from an oxide kathode is the same in 
oxygen and in hydrogen, gases which have very 
different chemical affinities for the material of the 
kathode, is evidence against the theory which has 
lately been put forward, that the electron emission 
from a glowing solid is due to chemical action between 
the solid and the surrounding gas.—W. S. Tucker: 
Heats of dilution of concentrated solutions. More 
detailed study of the variation of heat of dilution with 
concentration is here described than has hitherto been 
published. Dilution was performed by short steps by 
addition of water at air temperature. Specific heats 
of solutions were accurately obtained for various con- 
centrations so that heats of dilution could be calculated 
for any mean concentration. Solutions of hydrogen 
and lithium chlorides and sodium hydroxide give 
results which appear to show a linear relation with 
mass concentration, for the range over which heat of 
dilution has an appreciable magnitude. Curves are 
shown which indicate that this heat of dilution, if 
that linear relation be accepted, will vanish at such 
concentration as will suggest the formation of some 
simple hydrate of the solute. Thus the straight line 
connecting heat of dilution and mass concentration for 
hydrochloric acid solutions will, if produced, cut the 
axis of concentration at HCl,15H,O. Solutions of 
lithium chloride and sodium hydroxide similarly yield 
hydrates LiCl,8H.O and NaOH,8H,O.—T. R. Merton: 
The origin of the ‘ 4686” series. An attempt has 
been made to obtain some information as to the origin 
of the ‘‘4686”’ series by measurements | of the relative 
breadths of the “4686” line and the helium lines, from 
which the relative masses of the atoms concerned can 
be calculated according to the relations which have 
been found by Lord Rayleigh, Michelson, Buisson 
and Fabry, and others. The conclusion arrived at is 
that either the breadth of the “4686” line is controlled 
by circumstances at present unknown or that the line 
originates from systems of subatomic mass. 
Zoological Society, April 13.—Mr. E. T. Newton in 
the chair.—E. Gibson: The Nato cattle of the Argen- 
tine. The author exhibited the skull and a photograph 
of some specimens formerly in his possession which 
he believed to be the last of the breed.—Dr. G. E. 
Nicholls: The Urostyle (Os Coccygewm) of the 
anurous Amphibia.—G. A. Boulenger : The snakes of 
the Belgian and Portuguese Congo, Northern 
Rhodesia, and Angola. The paper contained a list 
of all the species known to inhabit this region, with 
keys to the identification of the genera and species, 
and the descriptions of two new forms from Angola 
and Katanga.—Dr. R. Broom: Some new carnivorous 
Therapsids in the collection of the British Museum. 
Most of the specimens described have been for many 
years in the collection, but owing to their small size 


