196 



IOWA ACADEMY OF SCIENCE 



results obtained in this laboratory by Stewart and by Brown as 

 well as by the writer, which indicated the presence of electrical 

 conduction between metal electrodes in air without actual metallic 

 contact of the surfaces, it was proposed by Stewart to use 

 Trouton's experimental method on metallic surfaces instead of 

 glass. The possibility was entertained that the pressure-mass 

 curve in the case of a metal would show the Trouton effect so 

 definitely that the beta condensation, or a similar type of con- 

 densation, could be held responsible for electrical conduction 

 across the gap observed to occur at a much larger distance be- 

 tween electrodes on a very humid day. It was hoped that the 

 Trouton drop in the case of a metal would be found near satura- 

 tion. 



The first metal tried was copper. It was considered desirable 

 to experiment simultaneously with glass wool in a separate ap- 

 paratus of the same kind, in order to learn whether the present 

 experimental conditions, somewhat modified from those of 

 Trouton, would give the same character of curve he obtained. 

 The outstanding modification of Trouton 's apparatus was a very 

 great refinement in the mode of feeding water into the glass wool 



C • * 



-4 



KJ 



!J 



Fig. 19. 



chamber subsequently to the drying, a refinement suggested by 

 F. C. Brown. "Without describing in the present report the re- 

 sults with copper, only the results with glass wool will be con- 

 sidered. 



