1879.] 
British Association. 
685 
rounding ether will be greater than before, and the ether, 
being in contact with the atom at its surface, will press 
upon it. The excess of ether about the vacant space above 
its original quantity constitutes the ethersphere ; and 
though this gathering together of ether about the space now 
occupied by the atom is a consequence of the presence of 
the atom, it is in no way owing to its aCtion on the ethereal 
medium. Mr. Earnshaw then argued that if every material 
atom, so must every compound system of atoms, i.e ., every 
material body, whether gaseous, liquid, or solid, have an 
ethersphere, which not only surrounds the whole body, but 
also penetrates the interstitial spaces of the body which lie 
between its atoms. By means of these etherspheres the 
author believes the phenomena of heat may be satisfactorily 
accounted for, on the supposition that the ethereal medium 
is the medium of heat as well as of light. He therefore 
concludes that etherspheres constitute a vera causa the 
existence of which in Nature is as certain as is that of the 
ethereal medium itself, about which no philosopher expresses 
doubt in the present day. 
Mr. Gordon read a paper on “ Secular Changes in the 
Specific InduCtive Capacity of Glass.” Mr. Gordon’s 
experiments have led him to the conclusion that in the 
course of a year and a half an aCtual change had taken 
place in the glasses he used, which was shown by a con- 
siderable real increase in their specific induCtive capacities. 
These experiments had some importance as regards Prof. 
Clerk Maxwell’s eleCtro-magnetic theory of light. In a 
recent leCture he (Mr. Gordon) had suggested that it was 
quite possible that the relation between eleCtric induction 
and light exists — namely, that they are disturbances of the 
same ether, but that there is some unknown disturbing 
cause affeCting the eleCtric induction. Possibly a clue to 
the nature of this disturbing cause may be found in the faCt 
that the specific induCtive capacities were affeCted by some 
of the changes which chemists assert are constantly going 
on in glasses, but that these changes do not affeCt the 
refractive indices. 
Prof. Johnstone Stoney read a paper “On the Cause of 
Bright Lines of Comets.” Dr. Huggins and others had 
seen the bright lines of the carbon speCtrum in the speCtra 
of several comets. This established the faCt that some 
compound of carbon was present in comets. Mr. Stoney 
suggested that the bright lines were due, not to the incan- 
descence of the carbon compound, but to the sun’s light 
VOL ix. (n.s.) 2 x 
