92 NOTICES OF THE MEETINGS [June 6, 
of late years been incorrectly represented comparatively to metallic 
oxides and ethers, and that the weight of alcohol which is truly 
equivalent to ether or water, is not 46 but 23. 
Having proved by a direct experiment that the formation of ether 
from alcohol is effected by substituting ethyle (C2 Hs ) for 4 of the 
hydrogen of that body, the process of etherification by sulphuric acid 
was explained by a diagram, on which half the hydrogen in sulphuric 
acid was shown to change places with its analogue ethyle in alcohol ; 
and that the peculiarity of the process, 7. e. its continuity, is owing 
to this change of place between hydrogen and ethyle, first taking 
place in one direction and then in the opposite ; that is, that sul- 
phuric acid becomes sulphovinic acid by taking up ethyle instead of 
an atom of hydrogen, and that it is then re-converted into sulphuric 
acid by resuming hydrogen instead of this ethyle, the first change 
forming water, the second ether. 
By using successively two different alcohols, it was shown that the 
two steps of this decomposition can be separated and their reality 
proved. The process of etherification is thus effected by a succes- 
sion of double decompositions, each of which considered individually 
is perfectly conformable to the law of definite proportions; but the 
alternation and continuous succession so clearly proved in them, is a 
fact unexplained by that law. A complete analogy between this 
process and the more familiar cases of chemical action is therefore 
only to be established by finding in these latter a similar atomic 
motion. 
A little reflection is sufficient to show that such a motion actually 
exists. The fact of diffusion is in reality nothing but a change 
of place between atoms, effected by the mere action of the particles 
on one another; and there are many mechanical evidences of the 
communication of momentum from masses to atoms, and inversely. 
It seems perhaps difficult to reconcile the apparent rest of the 
constituents of a mass with the existence of a continuous atomic 
motion ; but there are many cases in which a rapid and continuous 
motion produces to our senses the appearance of a phenomenon at 
rest: thus, the rapid revolution of a white sphere produces the 
appearance of a circle at rest when seen in front, and that of an ellipse 
when viewed obliquely. 
There are of course many points of view from which the motion 
of atoms may be considered; but it is inasmuch as it produces or 
facilitates decomposition, that the chemist has to regard it. We have 
in etherification an evidence of the tendency of atoms of analogous 
nature to change places continuously ; and it is natural to suppose 
that the facility of this interchange must be greater in proportion 
to the analogy between the molecules, and greatest between like 
molecules. The lecturer expressed a confident hope that he would 
soon be able to give a direct experimental evidence of this conclusion, 
and proceeded to show how the admission of it explains, without the 
supposition of occult forces, the occurrence of double decompositions 
and the action of masses. 
