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VII. An Attempt to Determine the Adiahatic Relations of Ethyl Oxide. 
By E. P. Perman, D.Sc., W. Ramsay, Ph.D., LL.D., F.R.S., and J. Rose-Innes, 
M.A., B.Sc. 
Received November 6,—Read December 10, 1896. 
The object of the research described in this Memoir is the determination of the 
behaviour of ether, in the state of gas, approaching towards the state of liquid, when 
no heat is communicated to it, so that its condition is altered adiabatically. Some 
experiments have also been made on liquid ether, an account of which we append. 
After several proposals, depending for their success on the sudden expansion of the 
substance, so that it might cool without sensible entrance of heat, recourse was had 
to a modification of Kundt’s process, whereby the velocity of sound in the liquid 
or gas is ascertained. The material for research, pure ether, was prepared and dried 
as already described in a paper by Dr. Young and one of the authors (‘Phil. Trans.,’ 
A, 1887, p. 57, et seq.). It had a constant boiling-point, identical with that already 
given. 
The experiments were carried out by Edgar Perman and William Ramsay 
during the Session 1891-1892. Various attempts were made to deduce from the 
results, by a graphical method, the true position of the curves representing the 
adiabatic expansion of the gaseous ether, but with small success. At a later date, 
J. Rose-Innes examined the figures contained in the tables annexed, and making 
use of the fact that, without serious error, the isochoric lines, as in the case of 
isothermal expansion, may be regarded as straight, contributed the mathematical 
treatment given in Section 5. 
For want of sufficient knowledge of the thermal data for liquid ether, a similar 
treatment has not been found possible; but it is the opinion of the authors that the 
experimental data should be published, inasmuch as they may be found in future to 
afford a means of determining the adiabatic relations of a liquid, of which the 
behaviour in the state of gas is now obvious. 
I. Apparatus Employed. 
The pressure apparatus. A, was the same as that employed in the former research, 
but important modifications had to be made, so as to render it fit for its present 
purpose. 
31.5.97 
