466 
its density. The physical methods of dif- 
fusion, and of measuring and comparing the 
refractivities of different gases and mixtures 
of gases, appear to have been carried to the 
highest degree of refinement which has yet 
been obtained, in this nominally chemical 
research. 
After adjourning to the Physical Lecture 
Theatre, the section took up the ordinary 
business of the meeting. A paper was read 
by J. A. Paterson, ‘On the Unification or 
Time,’ a question of considerable interest to 
Canadians. In the discussion, it was pointed 
out by Professor Rucker that, for the present, 
international agreement was hopeless. The 
question had recently been considered by an 
influential committee of the Royal Society, 
who had decided that the present was not 
a suitable time for action. A committee 
was subsequently appointed by Section A 
to consider what action could be taken in 
the matter. 
Professor Rucker, assisted by Forsyth and 
Sowter, showed some photographic records 
which had been obtained of objective Com- 
bination Tones, which were of great interest 
in connection with certain disputed points 
in the theory of such tones. 
The report of the Committee on Seismo- 
logical Observations was read by the Secre- 
tary, Mr. J. Milne. Among the points 
specially discussed were the greater fre- 
quency of sub-oceanic disturbances as com- 
pared with land-quakes, the large number 
of such movements originating in Tuscarora 
Deep being taken as a special example. It 
had also been shown by means of observa- 
tions of earthquakes taking place in various 
parts of the earth, and registered by means 
of one of Milne’s horizontal recording pen- 
dulums for unfelt earth-movements, that the 
velocity of propagation of such movements 
was much higher through the lower strata. 
The nearer the path to the center of the 
earth, the higher the velocity. By means 
of several of these instruments, which are 
SCIENCE. 
[N.S. Von. VI. No. 143. 
now being set up in different parts of the 
globe, it is hoped to obtain important in- 
formation with the regard to the interior 
constitution of the earth. Such records 
have also been proved to be of great prac- 
tical utility in connection with the breaking 
of submarine cables, and other effects of 
suboceanic disturbances. 
On Friday a paper was read by Dr. N. 
E. Dorsey, ‘On the Determination of Sur- 
face Tension by the Method of Ripples.’ 
Dr. Dorsey had applied the method used 
by Lord Rayleigh with great refinement to 
the measurement of the surface tension of 
water and of dilute aqueous solutions. He 
found that the surface tension was approxi- 
mately a linear function of the concentra- 
tion. ’ 
Professor H. L. Callendar and H. T. 
Barnes, of McGill College, Montreal, de- 
scribed their new method of determining 
the ‘Specific Heat of a Liquid in terms of 
the International Electrical Units.’ The 
practical details of the method have already 
been completely worked out, and several 
sets of observations have been taken in the 
case of water and mercury. The method 
consists in passing an electric current 
through a current of liquid flowing in a 
fine glass tube enclosed in a glass vacuum 
jacket, which is exhausted as perfectly as 
possible, and then hermetically sealed. 
The electric energy is measured by the 
potentiometer method in terms of the 
Clark cell and the Standard Ohm. The 
heat generated is measured by observing 
the flow of liquid and the steady difference 
of temperature between the ends of the fine 
tube. The time of flow is automatically 
recorded on an electric chronograph on 
which a standard clock is marking seconds. 
The difference of temperature is given by a 
single reading on a pair of differential 
platinum thermometers. 
The method was primarily devised for 
the purpose of investigating the question of 
