4 PROCEEDINGS OF THE AMERICAN ACADEMY 



again falls to 2.0, which is the same as that of solid paraffine. This 

 is the process used in preparing the " Faraday " cable. 



It is possible that the inferiority of the Patterson cable as compared 

 with the Faraday is due largely to the moisture retained in the cotton, 

 which we have seen has a capacity of 6.3. 



Leaving the paraffine cables, rubber is the next best, then gutta- 

 percha, and poorest of all is glass ; but all of these substances have 

 so high a specific inductive capacity aa to entirely unfit them for 

 telephonic work. 



RoGEBS Laboeatoet op Physics, 

 November, 1889. 



