.3901—2.] Mr J. Fraser on Constitution of Matter o.nd Ether. 35 
it to, yet it cannot be a solid like the solids of our experience, as 
the reader will see when I come to deal with the constitution 
of matter. What, then, is the bounding envelope resisting its 
outward pressure, spoken of by Herschel? I have pointed out 
that the probable cause of the pressure was the radiations of a 
practically infinite number of heated bodies in space — that in 
every direction in space some of those bodies were situated. 
Seeing, then, that it is the action of those bodies on the medium 
which causes pressure, the reaction of the medium on the bodies 
can only be equal to the action, not greater. In other words, the 
bodies are capable of resisting the pressure which they themselves 
produce; and as, ex liypothesi , they exist in every direction in 
space, there is the bounding envelope.* 
The Constitution of Matter. 
I come now to the consideration of the constitution of ordinary 
matter, that is, matter which we can see, or weigh, or perform 
other operations upon, — the ether, I need hardly add, eluding all 
cognisance of this kind. And yet, as I have hinted at the be- 
* It has been objected to the constitution of the ether herein set forth that 
it would be nothing more nor less than a gas. This objection I quote 
from Stallo’s Concepts and Theories of Modern Physics, p. 97 : — “The 
negative evidence here adduced against the supposition of an atomic or 
molecular constitution of the light-bearing medium is re-enforced by positive 
evidence derived from a branch of the atomic theory itself — the modern 
science of thermo-dynamics. Maxwell has remarked, with obvious truth, 
that such a medium (whose atoms or molecules are supposed to penetrate the 
intermolecular spaces of ordinary substances) would be nothing more nor less 
than a gas, though a gas of great tenuity, and that every so-called vacuum 
would in fact be full of this rare gas at the observed temperature and at the 
enormous pressure which the sether, in view of the functions assigned to it 
by the undulatory theories, must be assumed to exert. Such a gas, therefore, 
must have a correspondingly enormous specific heat, equal to that of any 
other gas at the same temperature and pressure, so that the specific heat of 
every vacuum would be incomparably greater than that of the same space 
filled with any other known gas.” I submit, it will be found further on 
that this objection is met by the difference which this theory assigns to the 
constitution of the ethereal atom from that of the material atom. The ethereal 
atom is a simple, structureless body, incapable of absorbing or retaining heat, 
simply passing it on as received from its neighbours on the one side to its 
neighbours on the other ; but the material atom and molecule are furnished 
with springs, so to speak, and upon which motion can be impressed so as to 
be retained by them for some time, until by their vibrations they gradually 
■communicate it to the ethereal medium. 
