arid Diathermancy of Air and Hydrogen. 



407 



In the subsequent experiments, the annular space between 

 the inner and outer glass cylinder was filled with water, at the 

 temperature of the room, up to within 7 millims. of the bottom 

 of the brass vessel. 



The effect of this alteration became at once apparent : the 

 deflections of the needle became less ; and the maximum effect 

 was more quickly attained. I give as illustration of this the 

 following series of experiments : — 



Table II. 





T. 



t. 



T. 



z. 



V' 



lOOr 



t ' 





rio-9 















739-5 





Dry air 



^38-3 

 134-0 



23-1 



20-5 



12 



— 



88-7 







ri2-8 















15 





Air- vacuum 



\ 41-5 

 37-1 



243 



310 



65 





144-6 











(35-15) 











rii-8 



— 











734-3 





Hydrogen- vacuum .. 



{ 40-5 

 [38-4 



26-6 



38-0 

 (50-45) 



7 



— 



190-0 





ri2-6 



— 











1-5 





Earefied hydrogeu.. 



\ 41-0 

 [36-9 



243 



360 



(45-5) 



6-5 



— 



187-2 



After removing the strip of silver intended to serve as screen 

 for the junction of the thermopile, the following figures, but 

 slightly differing from the previous ones, were obtained : — 



Table III. 





T. 



t. 



T. 



z. 



V- 



lOOr 



t ' 





rii-5 



\ 40-3 

 [35-1 



[12 1 



^39-8 

 [34-5 



rii-2 



^41-2 

 [37-0 



ri2-3 



J39-5 



[35-7 



236 

 223 

 25-8 

 23-4 







21-5 

 (21-63) 







32-0 



(36-9) 







42-0 



(62-6) 







34-0 



(41-2) 





 9 





 11 







6 





 6 



745-5 

 1-5 



749-0 

 1-5 



91-6 

 165-5 

 2426 

 175-8 



Air-vacuum 



Dry hydrogen 



Hydrogen- vacuum .. 



