Intelligence and Miscellaneous Articles. 73 



Ordinary Ether. 

 The tube contains the vapour of ether at a pressure of 0*07 metre. 



Radiation through empty trough . 28 Absolute loss 9*9 



troughfullofether 18-1 ^=0-35 



28 

 Ordinary Ether (vapour). 



Trough empty. 

 Radiation through tube containing I Absolute loss 10*2 



vapour under a pressure of O'OG I 28-6 Relative loss 0'356 



metre J 



Radiation through tube containing 1 



in addition the ether of the trough V 184 



vaporized J 



Formic Ether. 



The tube contains the vapour of ether under a pressure of O0S 



metre. 



Radiation through empty trough . 27*6 Absolute loss 7-3 



full trough .20-3 7 ' 3 _n-07 



" ° Relative loss -97^ 



Formic Ether (vapour). 

 Trough empty. 



Radiation through tube containing 1 ^o Absolute loss 8*5 



vapour at apressure of 0'075 metre J Relative loss 0*29 



Radiation through tube containing"] 



in addition the ether of the > 20*5 



trough vaporized .... J 



In another series of experiments on formic ether, the relative loss 

 due to absorption of the liquid was 0*28, and that produced by va- 

 pour 0-27. 



Professor Tyndall, in his researches on the absorption of heat by 

 gaseous substances, had dwelt upon the extreme energy which ether 

 vapour exerts upon obscure radiation. My experiments show that 

 the absorption exercised by this body on the rays of a lamp is also 

 very strong. 



A natural consequence of the preceding was that the heteroge- 

 neous radiation which I used, when it traversed a tube full of ether 

 under a pressure near that of the atmosphere, was more trans- 

 missible through liquid ether than it was when it had only passed 

 through vapour under a few centimetres pressure. In fact I have 

 seen the absorbing-action of ether almost double in consequence of 

 a diminution of about 0*58 metre in the pressure of the vapour of 

 ether in the tube. 



Finally, by working under different pressures, but always with 

 the heterogeneous radiation to which the bad condition of the atmo- 

 sphere has for some time condemned me, I have been able to ascer- 

 tain that ether vapour follows the law long known as that of the de- 

 crease of relative losses. By increasing the pressure from 10 to 10 



