412 



Scientific Proceedings, Royal Dublin Society. 



In this case the initial weight of the sample was 44-04 grammes, and the 

 final weight, after 677 hours' immersion, 47 - l grammes, thus giving a per- 

 centage increase in weight of 6 - 9. The area of the surface in contact with 

 the moist air was 155 sq. cms., and the specific resistance was 170 times the 

 resistance measured in megohms. 



The rapid decrease of resistance as more and more water was absorbed is 

 clearly shown by Table 5. This decrease for a given stage in the absorption 

 is probably caused chiefly by the continued penetration of the water absorbed 

 at earlier stages, and to a lesser extent by the water being absorbed during the 

 stage under consideration. 



Similar results were obtained for a tube of black fibre, and these are given 

 in Table 6. 



Table b\ 



Black fibre ; thickness, 0'6 cm. 



The initial weight, after drying, was 79 - 3 grammes, and the weight after 

 180 hours' immersion in moist air was 85 grammes, thus giving a percentage 

 increase in weight of 7"2. The area of the surface in contact with the moist 

 air was 178 sq. cms., and the specific resistance was 120 times the resistance 

 measured in megohms. 



In this case the decrease of resistance with time of exposure is much 

 greater than in the case of erinoid. This is mainly due to the fibre being 

 very much more hygroscopic than erinoid. 



More complete results were obtained for tubes of red erinoid and red fibre. 

 These are given in Tables 7 and 8. 



