JUNE 20, 1912} 
consistent with the restriction of the teaching at the 
Imperial College to post-graduate research work. Mr. 
Pease replied that the answer to the first part of the 
question was in the affirmative so far as the purposes 
referred to in Article Il. were concerned. When 
there was any proposal on the part of the governors 
to confine the work to post-graduate research, a 
question of the interpretation of the charter would 
arise, upon which he might have to express his 
opinion as visitor on behalf of the Crown. Until 
then he did not think he should be called upon to 
answer the question. In reply to a further question, 
Mr. Pease stated that no immediate alteration in 
substance was contemplated in the conditions for 
Royal scholarships or other awards in science. 
Tue Board of Education has recently issued a 
circular detailing the changes in the regulations re- 
specting the grants to be paid to technical schools for 
the session 1912-13 (Grant Regulations for Technical 
Schools, &c., Circular 795, Board of Education): The 
changes deal mainly with, first, the withdrawal of 
certain of the grants for agricultural education 
formerly paid by the Board of Etucation, and, 
secondly, certain modifications in the regulations re- 
specting the minimum length of “group courses” 
and the method of determining the minimum average 
attendance to be made by students at * group courses.”’ 
With respect to the first of these, “in consequence of 
the greatly increased amount of State aid which is 
now made available for agricultural education in 
county areas by the advance made to the Board of 
Agriculture out of the Development Fund,” the Board 
of Education will not pay grants for technical in- 
struction in agricultural subjects by any teacher 
recognised by the Board of Agriculture and Fisheries 
as a member of the staff of an agricultural college 
or of a county agricultural staff. The alterations in 
the regulations respecting group courses are in the 
direction of less stringency and more freedom to 
the institutions. Under the present regulations, no 
grant is made for instruction in any subject or course 
in which less than twenty hours of instruction is given 
in the year. The new regulations permit of courses 
in any subject for a less number of hours, provided 
that such instruction forms part of a “grouped 
course,’’ which must occupy, as at present, ‘‘at least 
four hours a week and eighty hours in all for the 
whole session.” In addition, 
fewer than ten hours each may be approved ‘in 
certain subjects (other than arithmetic, English, &c.) 
if they consist of concise and suggestive instruction 
given to students whose previous general familiarity 
with the subject enables them to profit by instruction 
of this kind.” 
SOCIETIES AND ACADEMIES. 
Lonbon. 
Royal Society, June 13.—Sir Archibald Geikie, 
K.C.B., president, in the chair—C. T. R. Wilson: 
An expansion apparatus for making visible the tracks of 
ionising particles in gases, and some results obtained by 
its use. The method of making visible and photograph- 
ing the tracks is essentially that described in a pre- 
vious communication. The apparatus has been en- 
larged and otherwise improved. The paths of alpha- 
particles are generally straight or nearly so until 
within about a mm. of the end (in air at atmospheric 
pressure) where they become bent. Portions of the 
tracks of beta-particles from radium have been photo- 
graphed, the individual ions set free being made 
visible by the cloud particles condensed upon them, 
so that they may readily be counted. The photo- 
graphs of the clouds formed when a narrow beam 
of X-rays is sent through the cloud chamber show 
NO. 2225, voL. 89] 
short courses of not | 
NATURE 
| 
| light on the connection between 
415 
the tracks of kathode or beta-particles starting within 
the primary beam and extending for some distance 
beyond it. There is no indication of any action of the 
| X-rays other than the production of the corpuscular 
rays. The corpuscular rays appear to start in all 
directions, showing no preference for that of the 
primary beam.—Hon. R. J. Strutt: Chemically active 
modification of nitrogen, produced by the electric dis- 
charge. IV. (1) Active nitrogen is a highly endo- 
thermic body, but its energy is of the same order of 
magnitude as that of other chemical substances. (2) 
In the reversion of active to ordinary nitrogen, the 
number of atoms ionised is a very small fraction of the 
whole number concerned in the change. The ionisa- 
tion is a subordinate effect, and may be due to light 
of very short wave-length emitted in the reaction. 
(3) Additional experiments are described to prove that 
the change of active nitrogen is more rapid at low 
temperatures. This is thought to be connected with 
the monatomic character of the molecule, and to throw 
temperature and 
velocity of reaction in other cases.—Prof. J. C. 
McLennan; The series lines in the arc spectrum of 
mercury.—Prof J. C. McLennan: The constitution of 
the mercury green line A=5461 AU; and on the mag- 
netic resolution of its satellites by an echelon grating. 
—Prof. W. H. Young: The convergence of certain 
series involving the Fourier constants of a function.— 
Prof. W. H. Young: Classes of summable functions 
and their Fourier series.—H. G. Moseley : The number 
of f-particles emitted in the transformation of 
radium. The number of _ 8-particles emitted 
at the disintegration of each atom has been 
determined by measuring the current carried in vacuo 
by the radiation from a known quantity of active 
material. It is found that one atom of radium B 
and an atom of radium C together emit 2°20 8-particles 
on an average; that an atom of radium B emits the 
same number of particles as an atom of radium C, 
and that an atom of radium E appears to emit less 
than one f-particle. From measurements of the 
ionisation produced by active deposit of radium emit- 
| ting a measured number of 8-particles, the number 
of ions produced by a B-particle per cm. of path in air 
has been calculated. This number varies approxi- 
mately as \3, where A is the absorption coefficient of 
the radiation for aluminium.—S. D. Carothers: Port- 
land experiments on the flow of oil. The paper was 
primarily the outcome of an attempt to obtain from 
the results of a series of experiments, which came 
into the writer’s hands, a relation between velocity 
and resistance for oil. It was seen that a consider- 
able number of the results of the experiments followed 
the capillary law, and attention was directed to deter- 
mining where this broke down.—G. B. Jeffery: A 
form of the solution of Laplace’s equation suitable 
for problems relating to two spheres.—A. Ll. Hughes : 
The emission velocities of photo-electrons. This in- 
vestigation was undertaken to determine the relations 
between the maximum velocity with which electrons 
are emitted from metallic surfaces illuminated by 
ultra-violet light and (a) the wave-length of the light 
and (b) the nature of the metal. 
Physical Society, Mav 21.—Prof. C. H. Lees, F.R.S , 
vice-president, in the chair.—Prof. G. W. O. Howe: 
The calibration of wave-meters for radio-telegraphy. 
Wave-meters consisting of a variable air-condenser 
and a set of coils can be calibrated approximately bv 
calculation from the known capacity of the condenser 
and the inductance of the coils. The most probable 
source of error is that due to the capacity from turn to 
turn of the coil. This can be allowed for, with 
| sufficient accuracy for all practical purposes, by find- 
ing the natural frequency of the coil alone, and 
