ll 
May 19, 1923] 
NATURE 
689 

Societies and Academies. 
Lonpon. 
Royal Society, May 10.—A. Fowler: The series 
spectrum of trebly-ionised silicon (Si IV). Numerous 
new lines of silicon have been observed and have 
been classified in four groups representing successive 
stages of ionisation. They have been designated 
Si I, Si I, Si III, and Si IV. The spectra consist 
alternately of triplets and doublets, and the series 
constant has successive values N, 4N, 9N, and 16N. 
For the series of Si IV the series constant is 16N. 
The spectrum is similar to that of neutral sodium, 
Na I. Including Paschen’s recent work on Al III, 
and the author’s previous work on Mg II, which 
also have spectra similar to that of Na I, data are 
thus available for the comparison of the spectra 
eee by four similarly constituted atoms, which 
iffer mainly in the charge of the nucleus. The 
highest limit of the Si IV system is 364,117, corre- 
sponding to an ionisation potential of 40-6 volts.— 
ir R. Robertson and W. E. Garner: Calorimetry 
of high explosives. A calorimetric bomb was devised 
in which high explosives could be brought to true 
detonation under comparable conditions as regards 
density of loading and confinement, without using 
a large quantity of explosive. In an explosive 
balanced in respect to total combustion, where it is 
possible to calculate values for heat of detonation 
and volume of gases, the results agree with theoretical 
calculations. The influence of the higher heat of 
formation of phenol with respect to toluene is reflected 
in the similar values for heat of detonation of trinitro- 
phenol and of trinitrotoluene, although the latter 
has much less oxygen for its combustion. The 
nature of the products, and the effect of conditions 
under which detonation is carried out on heat 
generated, and gaseous reactions involved, chiefly 
with regard to liberated carbon, are discussed.— 
H. S. Hele-Shaw: Stream-line filter. Very thin 
films of coloured liquid, or liquid containing matter 
in very fine suspension, either lose their colour in 
one case, or become deprived of their suspended 
matter in the other, on entering such thin films. 
In the new form of filter, sheets of paper made 
impervious to the fluid containing the suspended 
matter are arranged in a pack. By perforating the 
pack with a large number of holes it is possible to 
get the equivalent of a number of sources and sinks. 
his was obtained by using high pressures, so as to 
force the matter from one row of holes, acting as 
sources between the interstices of the paper, to another 
row of holes, each hole in the latter acting as a sink. 
Filtration can be made sufficiently rapid for actual 
use. The colouring matter of various dyes, from 
what were apparently complete solutions, can be 
removed, and substances like peat-water rendered 
clear and colourless.—F, W. Aston: A critical search 
for a heavier constituent of the atmosphere by means 
of the mass-spectrograph. The residues absorbed in 
charcoal from more than 400 tons of air were dealt 
with. Analysis with the mass-spectrograph gives a 
negative result and indicates that such an element 
certainly does not exist to the extent of 1 part in 
to" of air, and probably not to the extent of 1 part 
in 2x10" parts of air by volume. Faint bands 
observed in the region corresponding to masses 
150 and 260 were found: The first is due to a complex 
molecule of mercury with a multiple charge, but 
no ‘conclusion is reached in the case of the other. 
The results of the experiments are not in accordance 
with the presence of molecular krypton and xenon 
in the air, recently suggested.—H. E. Armstrong: 
The origin of osmotic effects. IV.—Hydrono- 
NO. 2794, VOL. 111] 
dynamic change in aqueous solutions, ‘‘ Water ”’ 
is a complex saturated with the gas Hydrone, OH,. 
Primarily, hydrone is the sole potentially “ active ”’ 
constituent, but it becomes actually active only under 
conditions which suffice to determine electrolytic 
change. The vapour pressure either of water or of 
a solution is the measure of the proportion of free 
hydrone molecules present in the liquid. Although 
the vapour pressure is lowered in the presence of 
any solute, the solution acquires attractive properties. 
The internal activity is increased while external 
activity is diminished. The effect produced may be 
ascribed to an interaction of molecules of the solute 
and those of hydrone. From non-electrolytes (under 
the influence of conducting impurity) a simple hydrol 
H 
is formed mc , only a single molecule of hydrone 
OH 
being “‘ distributed ”’ upon the molecule of the solute, 
whatever its magnitude. In the case of potential 
electrolytes, a reciprocal interchange of radicles of 
salt and hydrone is to be postulated. Not only is 
the solute hydrolated, but it is also distributed upon 
hydrone, the salt X’R’ giving rise initially to the 
reciprocal systems es 
R xf and H,OL 
‘Nou Nx 
As the concentration is lowered, under the influence 
H 
of hydrone, the complex R mC is more and more 
OH 
/OH 
Ultimately the 
NH 7 
R 
converted into hydvonol, H,O 
solution contains the solute only in the form HO 
together with an equal number of molecules of 
hydronol. The “ distributed ’’ reciprocal complexes, 
including hydronol, are the electro-chemical agents 
inasolution. The negative radicle in such complexes 
has greater residual affinity than it has in the original 
simple molecules. The osmotic pressure manifest in 
an aqueous solution is the pressure exercised by 
the extra molecules of hydrone attracted into it 
by the ‘‘distributed’” complexes, one by each com- 
plex, acting as though they were present in the 
gaseous state. In short, osmotic pressure developed 
within an aqueous solution, whatever the solute, has 
its origin in one and the same cause and is properly 
spoken of as hydrono-dynamic—if the word be per- 
missible: indeed, this term may be used as expressive 
of the general activity of water, electro-chemical and 
osmotic_—H. E. Armstrong: Electrolytic conduction : 
sequel to an attempt (1886) to applya theory of residual 
affinity. Referring to the distinction which he drew in 
1886 between simple and composite electrolytes—the 
former being electrolytes per se, the latter solutions 
of ‘“salts’’—the author directs attention to the 
diverse behaviour of the silver and lead haloids on 
electrolysis ; the current being carried, as it were, 
by the metallic ion of the silver and by the halogen 
of the lead compound. The conclusion is drawn 
that the salts of the two metals differ in structure— 
perhaps thus: 
Ag Ag Ag Cl Gl, (Gl 
To eae ae dilate 
{a Pb — Pb — Pb 
Ag Ag Ag Cl @ly"2- eh, 
The assumption is made that the primarily active 
unit is the fundamental molecule, and that the 
