898 REPORT—1885. 
mechanical contrivance at the command of those who would explain the funda- 
mental arrangement of the universe, and one which seems to promise great things 
besides possessing the inherent advantage of great simplicity. He then proceeded 
to explain, in a general way, how bodies in such a medium would—in virtue of 
the dilatation caused in the medium—attract each other at a distance, with a force 
depending on the distance, which might well correspond with the force of gravita- 
tion. Further, owing to the existence of a region close to the body in which the 
density varies several times from maximum to minimum, the mutual force might 
undergo a change from attraction to repulsion, and this more than once as the 
bodies approach—a condition which seems to account for cohesion and observed 
molecular force far better than any previous hypothesis. 
The transmission of distortional waves becomes possible if the medium be 
composed of small grains with large grains interspersed. The separation of two 
such sets of grains leads to phenomena closely resembling the phenomena of statical 
electricity. The susceptibility of such a medium for a state in which the two sets 
of grains are in conditions of opposite distortions may explain electrodynamic and 
magnetic phenomena, while the observed conducting power of a continuous surface 
for the grains of a simple dilatant medium closely resembles the conduction of 
electricity. 
2. On Calculating the Surface Tension of Liquids by means of Cylindrical 
Drops or Bubbles. By Professor G. Pirm, M.A. 
The author asserted that surface tensions are found only approximately and 
with difficulty by measuring the dimensions of round drops. He suggested that 
cylindrical drops should be used. He worked out the theory and described ex- 
periments of verification. 
3. On the Surface Tension of Water which contains a Gas dissolved in tt. 
By Professor G. Pirie, M.A. . 
The object of the experiments was to discover if water, which holds a gas in 
solution, has a different surface tension from water which holds no gas; and if it 
has to discover the law according to which increasing quantities of gas absorbed 
affect the capillarity. 
It was found that the surface tension is not measurably affected by those gases 
which, like air and carbonic acid, are not absorbed in sufficient quantities to affect 
markedly the specific gravity. A table of values of the specific cohesion was given 
for different quantities of two gases which are absorbed in large quantity. 
4, Thermodynamic Efficiency of Thermopiles.! 
By Lord Rayteicu, D.O.L., LL.D., F.R.S. 
5. On the Measurement of the Intensity of the Horizontal Component of the 
Earth's Magnetic Field.2 By THomas Gray, B.Sc., F.R.S.E. 
The general principle of the method adopted was that of Gauss, with these 
modifications. In the deflection experiment the magnetometer needle was made 
so short that in the calculations it could be assumed without sensible error to be 
of zero length, and two deflectors were used simultaneously. The deflectors were 
placed one on each side of the “magnetometer needle, with their axes in a line at 
right angles to the magnetic meridian ; and in position for deflecting the needle the 
direction of the line passing through the centres of the deflectors and the magneto- 
meter needle, were: first, the magnetic meridian, and second, a line at right angles 
1 Published in Phil. Mag. Oct. 1885. 
2 Published in Phil. Mag. Dec. 1885. 
