The Action of Metals^ &c.^ on India-rubber. 271 



intimate contact. In speaking on this subject to Mr. 

 Thomas Rowley, of Manchester, he informed one of us that 

 when he was an india-rubber manufacturer he had proofed 

 large quantities of cloth with rubber, and had a book in 

 which he kept samples of all he produced, many of which 

 were now 15 years old. It struck us that it would be 

 interesting to find whether any of the cloths which had been 

 so proofed, and which had remained good for so long, con- 

 tained copper, and Mr. Rowley very kindly placed his 

 pattern books at our disposal. These patterns were 

 arranged in numbers, describing the nature of the cloth and 

 kind of proof, etc., and dates. We selected 7 samples, all of 

 which, except one, had been steam vulcanized {i.e.\ sulphur 

 had been mixed with the rubber composition before proof- 

 ing, and the combination between the two brought about 

 by heating with steam afterwards. These patterns were 

 perfectly sound, although about 16 years old. 



We also selected one pattern of a brown cloth, in which 

 the rubber proofing was decomposed and hardened, and 

 which broke on the cloth being folded or bent. The follow- 

 ing is the list of the samples taken : 



Private 







Results 



Condition in 



Date. 



Description. 



of 



January, 









Analysts. 



i8gi. 



No. 1 10 



19 Nov., 1874 



Black alpaca. 



K copper 

 \ absent 



good 



„ 222 



18 Jany., 1875 



Black alpaca. 



j> 



>> 



,. 252 



22 ,, ,, 



Black Paramatta. 



»> 



>> 



„ 411 



2 April, ,, 



Blue black Paramatta. 



)) 



>> 



>» ~~ 



7 May, „ 



Black fine sheeting 



(cold vulcanized). 



>> 



)> 



„ 982 



28 Aug., „ 



Brown fine sheeting. 



j> 



>> 



„ II50 



24 Sep., „ 



Drab stout twill 



(black proofing). 



>» 



>> 



» 638 



25 June, „ 



Brown cambric 



(black proofing). 



trace 



quite de- 

 composed 

 and hard. 



All these samples were steam-vulcanized, except the 



