﻿irfyc.forP 



tire j 



Notes of 



■ different 1 



5 mi Hi in. 







v metre. 



1185 







1260-4 



1120 







1172*0 



1175 







1250-0 



1160 







1284-2 



1150 







] 223-3 



1145 







1217-9 



1220 







1297-5 



201 



Mean 1236-5 



Regnault gives 120077 and 1166-67, but these numbers 

 are probably too small. 



According to a few experiments which I made later with 

 coal-gas, the form of the apparatus that was used for carbonic 

 acid seems also suitable for gases lighter than air. In this 

 case, however, the observer must operate as rapidly as possible. 



§ 6. Mixtures. 



I also applied the method with good success to mixtures of 

 air and vapours. The form of the apparatus was the same as 

 for air, only that in this case the bottle was filled with the 

 evaporating liquid instead of with water. 



1 raised the liquid in the tube as far as the side piece A, 

 then let it slowly sink and remain standing for a time, which 

 varied from a few seconds to two hours. The temperature 

 for all the experiments was constant (17° C). With tube II. 

 and fork c nl 1 took six sets of readings given below. At the 

 beginning of each set, one or two half wave-lengths come 

 where only very little vapour was present. Then with in- 

 creasing saturation the half wave-lengths gradually decrease, 

 until in the immediate neighbourhood of the liquid they 

 become constant. 



Experiments with Ethyl-ether Vapour. 





1. 



2. 



3. 



4. 



5. 



G. 







Surface of ether 



below. 







* millim. 



= 160 



153 



— 



156 



153 



159 



2 



1-14 



154 



145 



151 



153 



156 





130 



1-13 



130 



132 



132 



132 





109 



110 



108 



•112 



110 • 



114 





108 



110 



114 



112 



112 



112 





112 



110 



no 



113 



113 



110 





100 



109 



109 



110 



110 



110 



Surface of ether above. 



