384 
Proceedings of the Royal Society 
In gases the intervals between the atoms must be enormous, and yet, 
if the old theory of repulsion holds, the atoms still repel one another, 
even under the nearly fully exhausted receiver of an air-pump. 
4^/i, A ray of light falling on a polished surface of coloured glass, 
or on a mahogany table, &c., is reflected without acquiring any of 
the colour of the body reflecting it. This proves that the action in 
reflection is external to the substance of the glass, and that the ray 
never touches the reflecting surface. 
The fact with regard to light, that the angle of reflection is equal 
to the angle of incidence, and that there is no dispersion of the ray, 
owing to the necessary roughness of all artificially polished sur- 
faces, is, as Sir John Herschel observes, in his article on light 
(Ency. Metr.), a proof that the ray never touches the surface, but is 
reflected at a certain distance from it. 
The passage of the refracted ray after it has passed through 
the band of force (where it is bent down towards the glass), and 
comes upon the partially rough substance of the glass, affords a 
strong proof that it does not encounter matter there to obstruct or 
scatter it, for it meets the surface at every conceivable angle, and 
yet the different parts of the ray pass through all the inequalities, 
preserving their direction parallel with one another. We must 
therefore regard the surface of the glass as merely the first line of 
centres of the atomic forces which constitute the substance of the 
glass, and which centres terminate again in the line of the lower 
surface of the glass. 
6^^, The free vibration of the ether in the densest bodies, such 
as the diamond, ruby, glass, water, and crystals, and the parallel 
direction of the luminiferous ray, is not reconcilable with the theory 
of transparent bodies being solid and natural bodies. 
Ithj Our inability to interrupt the attracting action of the magnet 
by the intervention of numerous plates of non-magnetic dense 
bodies, such as glass, copper, lead, pasteboard, &c., either singly or 
in combination, affords a strong presumption that all these sub- 
stances interposed are composed not of solid matter, but of com- 
binations of immaterial forces. 
It is evident from the above facts and considerations that we 
never touch matter (even if it exists). And that we never see it is 
admitted alike by physiologists and metaphysicians, for vision is 
