830 
NATURE 
[JUNE 16, 1923 

are given.—C. R. Darling: An experiment on the 
production of an intermittent pressure by boiling 
water. If a glass tube, open at both ends, and of 
about 5 mm. bore, be stood in a beaker of boiling 
water, steam bubbles form at the point of contact, 
causing the water to rise in the tube. The column 
of water sinks after a time, and then rises again, the 
rising and falling occurring at irregular intervals. If, 
however, the tube be narrowed to about 1 mm. near 
the top of the water, and widened out considerably 
just above the water surface, the action becomes 
regular. The water is apparently superheated at the 
points of contact of the tube and beaker, so that the 
steam produced can sustain a higher pressure of 
water. When the water reaches the widened part 
it is cooled and increases in density until the extra 
steam pressure at the bottom of the tube is overcome, 
when it discharges completely. The capillary bore 
slows down the rate of flow in both directions. A 
separating funnel with open tap and short stem is 
well suited to the experiment. The arrangement 
constitutes a simple heat engine, with source and 
sink, automatically passing through a regular cycle 
of operations.—N. W. McLachlan: A novel instru- 
ment for recording wireless signals. The device 
consists essentially of a drum of Swedish iron with 
an annular recess in which are situated coils of fine 
wire, the ends of the coils being connected to corre- 
sponding slip rings. The periphery of the drum is 
faced with cast-iron rings. A small steel shoe rides 
on the rings, and side play is prevented by a brass 
guide-piece with a projection which fits into the 
annular recess. At each end of the guide-piece a 
hook is formed, and one of the hooks is connected by 
a light rod to a duralumin lever pivoted to turn in a 
horizontal plane. A silver syphon passes through 
the lever and rests lightly on a moving paper tape. 
The drum is revolved by a small electric motor, and 
when a current flows in one of the coils the shoe is 
attracted to the drum and a large pull is required 
to prevent relative motion of the two. This pull 
actuates the syphon-lever mechanism, which can be 
used to show the dots and dashes of the Morse code. 
The instrument is extremely sensitive, and will work 
at a speed of 150 words a minute with a current of 
25 micro-amperes. 
EDINBURGH. 
Royal Society of Edinburgh, May 21.—Prof. F. O. 
Bower, president, in the chair.—A. P. Laurie: An 
interesting property of the water molecule. On a 
modification of Langmuir’s theory of chemical com- 
bination, namely, that the two nearest magnetons of 
two approaching atoms, forming the Langmuir pair, 
move outwards laterally in opposite directions, thus 
binding the two atoms together as one common 
molecule, a water molecule has four external mag- 
netons, in addition to the four which are attaching 
the two hydrogen nuclei. This molecule can, there- 
fore, form groups combining one with another 
to give hollow shells or rings which have the pro- 
perty, peculiar to water alone, of having no external 
magnetons. In the same way, the hydrates formed 
by combining water with a molecule or ion have no 
external magnetons, the result being the formation 
in solution of molecular groups, which may be 
regarded as chemically neutral to each other. They 
can account for the properties of water solutions of 
salts, resulting in their obeying the gas laws in dilute 
solutions, and also for the part played by water as 
the only possible medium for organic life —H. Stanley 
Allen: A static model of the hydrogen molecule. A 
theory of the constitution of molecules is developed 
on the basis of the ‘‘ quantum force ’’ introduced by 
NO. 2798, VOL. 111] 
Langmuir with the view of securing a static model 
of the hydrogen atom. It is here assumed that the 
“quantum force,’ which, like the repulsive force 
employed by Sir J. J. Thomson in the same problem, 
varies inversely as the cube of the distance, is a 
repulsion or an attraction according to the sign of 
the electrical charges between which the force acts. 
On this assumption a hydrogen molecule is possible, 
having many of.the properties of the molecule 
imagined by Bohr but with the electrons at rest 
relatively to the hydrogen nuclei. Various configura- 
tions of equilibrium are theoretically possible, but 
not all of these are stable. The calculated ionisation 
potentials are in moderately good agreement with 
the experimental results. Though the numerical 
values may need modification, it is now possible to 
postulate a hydrogen molecule in which the electrons 
are at rest instead of in orbital motion. The prin- 
ciples may be applied to more complex atomic and 
molecular systems.—Henry Briggsand John Mallinson: 
Further tests upon metal Dewar flasks intended to 
hold liquid air. The pressure in the vacuous envelope 
was obtained by direct measurement, and a series of 
results are given for British- and German-made flasks 
of different kinds. Radiation is by far the chief 
source of heat transfer in a flask holding liquid air, 
and further improvement is to be sought only by 
better attention to the polished surfaces. Losses by 
conduction down the neck and (unless the vacuum 
has much deteriorated) by conduction across the 
vacuous space are generally relatively small in 
amount. The charcoal used makes it unnecessary to 
evacuate by pumping to a pressure of less than oT 
or 0-2 mm. of mercury. 
SHEFFIELD. 
Society of Glass Technology (at University College, 
London), May 16.—Prof. W. E. S. Turner, president, 
in the chair.—F. Twyman and F. Simeon: On the 
refractive index changes in optical glass occasioned 
by chilling and tempering. Chilling dense barium 
crown and borosilicate crown glasses may lower the 
refractive index by as much as 0-004 and 0-0013 
respectively. This lowering of refractive index can 
be removed by heating to a temperature and for a 
length of time which have been ascertained in certain 
cases. A want of homogeneity can be produced by 
moulding, owing to surface chilling, which requires 
for its removal a longer maintenance at the high 
temperature than would suffice to remove elastic 
stress from a homogeneous sample.—V. Stott: Notes 
on burettes. Accurate readings can be obtained 
much more quickly by using a long emptying time 
and a short drainage than by using a short emptying 
time and a correspondingly longer drainage time: 
The errors occurring through using a burette cali- 
brated for a certain delivery time, with a jet which 
gave a different delivery time are, in some Cases, too 
large to be negligible-—A. Ferguson: A new method 
of glass-melting. The process consists of employing 
a cone or column of whirling gases at 1800° C., into the 
vortex of which batch ground to a 60-mesh standard is 
dribbled at the rate of two pounds per second; the 
carbon dioxide of the limespar and soda ash is first 
driven off in a preheater, so that the work of the 
furnace is only to raise the temperature from 850° C. 
to 1350° C. instead of from 20° C. All reactions 
necessary to form glass molecules take place in a 
gas at least two million times less viscous than tank 
metal.—S. English: Natural sillimanite as a glass 
refractory. This material possesses properties of 
considerable value to glass-makers. Test pieces were 
made up by mixing 100 parts of sieved sillimanite 
with ro parts of finely ground ball clay ; such a mixture 
