L891."| On the Adialatic Relations of Ethyl Ox'ule. 



441 



[I. u An Attempt to determine tlie Adiabatic Relations of Ethyl 

 Oxide. Part I. Gaseous Ether." By W. RAMSAY, F.R.S.. 

 Professor of Chemistry in University College, London, and 

 E. P. PERMAN, B.Sc. Received March 16, 1891. 



(Abstract.) 



The object of the research described in the memoir is the determi- 

 lation of the behaviour of ether in the state of gas approaching 

 >wards the state of liquid, when heat is communicated to it, so as to 

 Iter its condition adiabatically. 



Previous researches by one of the authors in conjunction with 

 )r. Sydney Young have yielded data regarding the relations of 

 pressure, temperature, and volume of gaseous and of liquid ether 

 rom which tt e values of the isobaric and of the isochoric differentials 

 ire obtainable. Such results lead directly to a knowledge of the 

 lifferences between the specific heats at constant pressure and those 

 it constant volume ; and these differences are not constant, but vary 

 rith varying volume, pressure, and temperature. 



The memoir contains an account of experiments made to determine 



the ratio between the specific heats at constant pressure and those at 



jnstant volume. The velocity of sound in gaseous ether was 



letermined at various temperatures, pressures, and volumes; and by 



leans of the isothermal differentials, and the experimental results 



for the velocity of sound, the ratios between the two specific heats 



rere calculated. From the differences and the ratios of the specific 



icats, the values of the specific heats were deduced. 



The general conclusion is that, for any constant volume, the specific 

 leat, whether at constant volume or at constant pressure, decreases 

 a limiting value with rise of temperature, and subsequently 

 icreases ; and that the change with temperature is more rapid, the 

 laller the volume. 



At large volumes, the specific heats tend towards independence of 

 jrnperature and volume, while at small volumes, the influence of 

 ihange of temperature and volume is very great. 

 The authors are at present investigating similar relations for liquid 

 sr. 



