, ——e—eEeEeEeEeEeEeEeEeEeeeEeEeEeEeEeEeEeEeEeEeEeEeEeEeEeEeEeeeeEeEeEeEeeeeeEeEeEEEEEE 
May 30, 1912] 
NATURE 
337 
to the conduct and capacity of the holder by the 
authority under whose supervision the scholar is 
placed by the Board. The scholar will be required, 
as a general rule, to spend some part of the three 
years at an approved Continental laboratory or 
university. An applicant for a scholarship must be 
(a) a graduate of a university, or (b) the holder of a 
diploma of a university or college of university rank. 
He must be nominated by a professor or lecturer of 
a university or college of university rank. Nomina. 
tions must be received not later than June 17. 
Tue sixth annual report, that for 1911, of the 
Apprenticeship and Skilled Employment Association 
shows that with the advent of the juvenile advisory 
committees—now established under the Board of 
Trade in connection with every labour exchange in 
London—there has still been scope for the work of a 
voluntary society in the organised effort to improve 
the industrial conditions of young people. During 
the year a working scheme of cooperation has been 
devised between the association and the official 
juvenile advisory committees. The Board of Trade 
has shown its recognition of the work done by the 
association by nominating many of the members of 
its affiliated committees to serve on the local juvenile 
advisory committees. The functions of the associa- 
tion are of a twofold character: through its local 
committees it places children as they leave school in 
situations where an adequate industrial training may 
be secured, and the central office serves as a co- 
ordinating body, collecting industrial information 
and acting as a clearing-house in the matter of 
vacancies. The friendly relations that have always 
existed between the London County Council and the 
association have been maintained. As in the past 
two years, the central office has, at the request of 
the Council, continued to place laboratory monitors 
in work as they leave the Council’s service. The 
finances of the association are not in the satisfactory 
condition the excellence of its work merits, and an 
appeal is made in the report for further assistance. 
Donations may be sent to the honorary treasurer at 
the office of the association, 36 Denison House, Vaux- 
hall Bridge Road, London, S.W. 
SOCIETIES AND ACADEMIES. 
LonpDoNn. 
Physical Society, May 10.—Prof. A. Schuster, 
F.R.S., president, in the chair.—Dr. J. A. Harker 
and Dr. G. W. C. Kaye: The generation of electricity 
by carbon at high temperatures. The experiments 
described owe their origin to some contamination 
phenomena which were encountered when tubes of 
refractory rare earths were baked in carbon-tube 
resistance furnaces at temperatures from 1500° C. 
upwards. It was found that the tubes often had their 
outer surfaces carbonised to an appreciable depth, 
while the inner surfaces, though freely exposed, were 
much less attacked. The blackening was presumably 
caused by particles shot from the carbon walls of the 
furnace with velocity high enough to penetrate the 
refractory material after crossing a few millimetres 
of air at atmospheric pressure. The preliminary 
experiments on the nature of these particles were 
carried out by the use of two insulated exploring 
electrodes of carbon inserted into an alternating- 
current furnace. They were connected externally to 
a battery of cells, and the potential-current curves 
were determined for the electrode gap in the furnace 
at a number of temperatures. -No appreciable 
current could be detected at temperatures below 
about 1400° C., but as the temperature rose it was 
found that quite small E.M.F.’s gave rise to steady 
NO. 2222, VOL. 89] 
currents of relatively enormous magnitude. For ex- 
ample, with 8 volts, currents up to 10 amperes have 
been obtained at a temperature of about 2500° C. 
The relation between current and temperature was 
found to be of an _ exponential character.—S. 
Butterworth: A method of measuring small induct- 
ances. The author shows how Anderson’s method 
may be modified so that, while still retaining the 
usual standards of capacity, very small inductances 
may be measured. As in Anderson’s method, balance 
is attained by a simple resistance adjustment. The 
conditions of maximum sensibility are indicated, and 
experimental results are quoted in which an induct- 
ance of 20 microhenries is compared with a capacity 
of o-t mfd. The method may also be employed to 
compare a very low capacity with the usual mica 
standards of capacity—H. A. Colwell and Dr. S. 
Russ: The conversion of starch into dextrin by 
X-rays. When solutions of starch are irradiated for 
several hours by X-rays of moderate penetrating 
power, the opacity and viscosity of the solutions are 
markedly diminished. .These physical changes are 
attended by chemical changes; there is a partial con- 
version of the starch into soluble starch and dextrin. 
A quantitative estimation of the amount of dextrin 
formed after the starch solution had been irradiated 
for eight and a half hours showed that it corre- 
sponded to about 5 per cent. of the amount of starch 
initially present. When solutions of dextrin were 
subjected to a similar exposure of X-rays, no con- 
version of this substance into glucose was obtained. 
Institution of Mining and Metallurgy, May 16.—Mr. 
Edward Hooper, president, in the chair.—J. B. 
Tyrrell: The law of the paystreak in placer deposits. 
This paper embodied the results of a study of the 
placer deposits of the Klondike district with the view 
of determining the laws which govern the deposition 
of placers and the formation of the run of coarse gold 
usually found in the bottom of the larger valleys. 
The author believed that the laws or principles he 
enunciated with reference to the Klondike have a 
general application to the concentration of heavy 
metals or minerals in alluvial deposits. He then pro- 
ceeded to describe the various stages of development 
which the existing valleys have undergone with the 
view of showing the probable course of events which 
have resulted in the present position of the “ pay- 
streak.’—F. Percy Rolfe: Ilogical precision in mine 
reports. The author of this paper directed attention 
to the prevalent custom of expressing large tonnages 
to the extreme accuracy of a single ton, and of report- 
ing mine assays to excessive minuteness, and he aimed 
at showing that such practice is inconsistent, since 
the same or a greater actual degree of accuracy can 
be attained by simpler “round figures.”” He gave 
examples in illustration of his contention to show 
what varying results may be obtained according to 
the “personal equation” of the mine engineer or 
assayer. For example, a reserve of ore was separ- 
ately estimated by two experts, each estimate being 
expressed to the accuracy of one in a million, while 
the two varied to the extent of one in ten, the differ- 
ence being considerably more than 100,000 tons. 
Similarly, in mine assays, values are given at times 
to a single penny, when assay results taken from 
different parts of the face show wide variations from 
which an average value can only with difficulty be 
deduced to the limits of accuracy of a shilling unit. 
—Leon Perret: Gold and platinum alluvial deposits 
in Russia. This was an exhaustive review of the 
growth and present position of gold and platinum 
alluvial mining in Russia, and contained a number 
of interesting details in relation to the special condi- 
tions necessitated by climatic and other peculiarities. 
