[ 405 ] 



XXXII. 



THE ABSORPTION OF WATER BY VULCANIZED FIBRE AND 

 ERINOID ON EXPOSURE TO MOIST AIR, AND THE CONSE- 

 QUENT CHANGE OF ELECTRICAL RESISTANCE. 



By R. G. ALLEN, B.Sc, Lond. ; A.R.C.Sc.T. ; 

 Assistant to the Professor of Applied Physics in the Royal College of 



Science for Ireland, Dublin. /<e^ S 



V AUG i , 



% 



■ 



(COMMUNICATED BY PROFESSOR WILLIAM BROWN.) 



[Read Juke 25 ; published October 2, 1918.] IVIUS ^ 



The absorption of moisture by erinoid and fibre when directly immersed in 

 water for a certain time, and the electrical resistances of these materials in 

 their ordinary .physical states at different temperatures, have already been 

 investigated by the author. 1 The present paper deals with the absorption of 

 water by fibre and erinoid when exposed to moist air, and the consequent 

 change in their electrical resistances after different times of exposure. 



The absmytion of water with time of exposure. 



Samples of fibre and erinoid were first well dried in an air-oven and 

 afterwards weighed. They were then immersed in nearly saturated air for a 

 certain time, and weighed at intervals. The arrangement used for producing' 

 the moist air consisted of a large glass vessel, containing water to the depth 

 of about two inches and fitted with an air-tight lid. A narrow glass 

 platform was fixed well above the surface of the water, and upon it was 

 placed a wet and dry bulb thermometer. The samples were suspended in the 

 air close to the hygrometer. This air was not quite saturated, but the 



1 Scient. Proc. Roy. Dubl. Soc, 1918, vol. xv. (N.S.), No. 29, p. 331. 



SCIENT. PROC. R.D.S., VOL, XV.. NO. XXXII. 3 T 



