1904 - 5 .] Mr J. Fraser on Electricity based on Bubble Atom. 699 
the upper part of the disc is touched motion flows in from the earth 
through the operator’s body and neutralises the negative electricity 
on the upper part of the disc, so that upon raising it from the cake 
it is found to he charged with positive electricity. If the disc 
remained on the cake while charged I have no doubt that the 
charge would slowly dissipate itself over the surface of the cake, 
and the reason it does not at once do so is, as it appears to me, 
the bad-conducting qualities of the cake ; but, as it appears to me, 
the disc, uncharged, might remain any length of time in contact 
with the negatively electrified cake without the disc losing any of 
its positive electricity, because, although the disc’s positive was in 
contact with the cake’s negative, the tendency for the positive to 
go back to its own negative would be at least as strong as the 
tendency to neutralise the negative of the cake, nay, more so, for 
the disc is a conductor, and the cake a non-conductor. 
26. Specific Inductive Capacity. 
Some substances, such as glass, etc., if placed between an 
electrified body and a conductor not electrified, cause a greater 
induced charge to appear on the latter than if they were absent. 
The reason for this, as it appears to me, is as follows : Suppose 
the electrified body, or the supply of electricity from a machine, to 
be positive, then the extra pressure from the positive body to 
which the glass, or other dielectric, is subjected compresses the 
atoms into a smaller space, and since, practically, all the motion is 
conserved to each atom, none of it being able to escape, owing to 
the non-conductivity of the dielectric, the speed of the particles 
greatly increases by the conversion of their potential into actual 
energy. By the increase in their speed they absorb and radiate a 
greater quantity of the radiations , not only from the electrified 
body but from all other directions (see p. 41 of paper on “ Con- 
stitution of Matter,” etc.) ; not only so, but, by the contraction of 
their orbits, their “centrifugal force” is increased, and there is 
good reason to suppose, as will appear later, that the speed of the 
particles of dielectrics is far greater than that of those of conduct- 
ing bodies. For these reasons it will be apparent, then, that by 
the interposition of the dielectric the body under induction will 
