The British Association. 
513 
18 78.] 
Prof. J. D. Everett read the “ Report of the Committee 
on Underground Temperatures.” The principal novelty 
was the proposal to make observations in filled-up bores by 
a thermo- electric method. Two wires, one of iron and the 
other of copper, each covered with gutta-percha, were to be 
joined at both ends, where a portion would be left uncovered. 
One junction would be buried in the bore, while the other 
would remain above ground, available for observation. A 
current would flow through the circuit composed of these 
two wires whenever the two junctions were at unequal tem- 
peratures, and the observer would immerse the accessible 
junction in a basin of water containing a thermometer, and 
would regulate the temperature of the water until he found 
by a galvanometer that no current passed. He would then 
know that the temperature of the water, as indicated by 
the thermometer, was the same as that of the buried 
junction. 
The “ Report of the Committee for the Determination of 
the Mechanical Equivalent of Heat ” was then read. The 
Committee are now making a more accurate investigation 
of the true position of the freezing- and boiling-points of 
the thermometer when cleared from the effects of the 
imperfedt elasticity of the glass of which they are con- 
strutted. 
Papers were read by Mr. J. E. H. Gordon, “ On some 
Experiments on Specific Inductive Capacity,” and “ On the 
Effedt of Variations of Pressure on the Length of Disruptive 
Discharge in Air.” 
Mr. G. Johnstone Stoney communicated the results of 
long investigation, by himself and Prof. J. Emerson Rey- 
nolds, “ On the Spedtrum of Chloro-chromic Anhydride.” 
He ^described the kinetic theory of gas molecules darting 
about and continually striking against each other ; but, be- 
sides these, he said there were internal motions within the 
molecules, which in many cases were either periodic or 
quasi-periodic. The evidence of this was obtained from 
the spedtra of gases. For many years he had been engaged 
in searching for cases of harmonic motion in gas, and, with 
the assistance of Prof. Reynolds, he had obtained the posi- 
tions of 105 lines in the spedtrum of chloro-chromic anhy- 
dride, which proved to be harmonics of one particular 
motion. The time of one of the oscillations had been mea- 
sured to the 810,000,000,000th part of a second. 
Prof. James Thomson next read a paper “ On the Flow 
of Water in Uniform Regime in Rivers and in Open Chan- 
VQL, VIII, (n.s.) 2 L 
