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XXIX. 



THE INSULATING PEOPEETIES OF ERINOID. 



By R. G. ALLEN, B.Sc., Lond. ; A.K.C.Sc.1. ; •""tthsi 



A? 



Assistant to the Professor of Applied Physics in the Eoyal College oj^ 

 Science for Ireland, Dublin. 



(COMMUNICATED BY PEOFESSOR WILLIAM BROWN.) 

 [Read April 23 ; published August 16, 1918.] 



Tins paper deals with the results of an investigation of some of the properties, 

 chiefly relating to insulation, of Erinoid 1 — a material of comparatively recent 

 origin, which, among other purposes, is used as an insulator. 



A few preliminary tests were made on several samples of erinoid. Thus 

 it was found to have a density T34 at ordinary temperature ; to soften 

 somewhat when immersed in boiling water for a short time ; that when 

 immersed in heated olive oil at a temperature of 200° C. for some minutes 

 and then removed it readily disintegrated into the form of a burnt powder ; 

 to be non-inflammable, and apparently unattached by dilute sulphuric acid of 

 density 1*2 after immersion therein for over a week; to have considerable 

 mechanical strength and be easily machined into various forms. 



It was thought desirable, for the sake of comparison, to similarly test 

 under the same conditions as nearly as possible some other insulating 

 material in common use, and the one selected as being perhaps the most 

 representative was red vulcanized fibre, which will generally be referred to 

 as red fibre. 



The samples used in this investigation had been previously exposed to 

 air under ordinary conditions in a dry room for several months. Some of 

 these were in the form of short cylindrical tubes, closed at one end, and 

 turned in a lathe. Others were in the sheet form, with unmachined surfaces. 



Absorption and Retention of Water. 



The samples in the form of solid cylinders or plates were first weighed in 

 air, Wi grammes ; immersed in water at ordinary temperature for t, hours ; 



1 This material ia a by-product of milk ; the process of its manufacture, which is 

 complicated, being partly mechanical and partly chemical. It is extensively used for 

 various purposes in many countries. For further information, see Whitaker, 1918 : A 

 New British Industry, p. 820. 



SCIENT. PROC. R.D.S., VOL. XV., NO. XXIX. 3 H 



