•114 Scientific Proceedings, Royal Dublin Society. 



Tables 7 and 8 show the great decrease of resistance in fibre 1 and erinoid 

 with increase in the quantity of water absorbed. The decrease is enormous 

 in the case of fibre between the absorption of 2 - 46 and 5-3 grammes of water. 

 This suggests that a rapid penetration of the liquid across the thickness of 

 the material was taking place at that stage in the absorption. 



In conclusion, the results of this investigation are : — 



1. Vulcanized fibre is much more hygroscopic than erinoid. 



2. After having been thoroughly dried, and then exposed to moist air, the 

 electrical resistance of both fibre and erinoid, especially the former, rapidly 

 decreases as time of exposure continues. Thus the decrease of specific 

 resistance of a sample of red vulcanized fibre after 82 hours' immersion in 

 nearly saturated air, was from 2 - 2 x 10 6 to 109 megohms per cm. cube; and 

 for a sample of red erinoid, after 83 hours' immersion, from 9-9 x 10 6 to 

 0-49 x ] 6 megohms per cm. cube, a very much smaller percentage decrease 

 than that of the former material. 



3. "Whatever the quantity of absorbed water in the sample, the same 

 simple relation between temperature and resistance was found to be followed 

 by fibre and erinoid. This gives strong support to the theory that electricity 

 is conducted through insulating materials by the vehicle of water-films. 



1 For the range of absorption given in Table 8, beginning at 25 hours, the resistance 

 of the red fibre at 30° C. will be found to be approximately proportional to x 8 ' 7 . The 

 corresponding index of x for the red erinoid is very roughly - 12. 



