Ai,lkn — Absorption of Water by Vulcanised Fibre aad Erinoid. 411 



Kasch and Hinrichsen and others have found for certain materials, that 

 the graph of the reciprocal of absolute temperature and the logarithm of 

 resistance is a straight line. 1 The former workers showed it was followed by 

 such substances as porcelain, glass, oil, water, and ice. The same result was 

 previously found, by the author, for both erinoid and fibre in their ordinary 

 physical states. 2 Jt would seem that this relation is generally followed by 

 insulating materials. 



In the present investigation the same relation between — and Log. 11 



was found to be followed by both fibre and erinoid in every case, whatever 

 the quantity of water absorbed. This is an important result, for it gives 

 strong support to the theory, propounded by Evershed, that electricity is 

 conducted through an insulating material by means of an internal system of 

 water-films. 8 



Straight-line graphs, twenty-seven in number, were drawn according to 

 the data of tables such as 3 and 4, and from them the resistances at 30° 0., 

 40° C, and 50° 0. were obtained for each stage of immersion in the moist air. 

 The resistance was measured by means of the leakage method, using an 

 electrostatic voltmeter and mica condenser in parallel with the sample. 4 In 

 some cases the megger was used. The results obtained for blonde erinoid for 

 different times of immersion in moist air are given in Table 5. 



Table 5. 

 Blonde erinoid ; thickness - 38 cm. 



1 Zeit. Elektrochem., Bd. xiv, 1908, p. 41. 



2 Scient. Proc. Roy. Dub. Soc, 1918, vol. xv. (N.S.J, No. 29, p. 350. 



3 Journ. Inst. Elec. Eng., vol. lii, 1913, No. 224, p. 51. 



4 For the arrangement used, see Scient. Proc. Roy. Dub. Soc, 1918, vol. xv. (N.S.), 

 No. 27, p. 292, 



