154 GOODYEAR ON GUM -ELASTIC, 



paper. Upon being further questioned, he brought a little parcel 

 of the gum, about as fine as mustard seed, which was separated 

 from the rags by the engine. The idea was suggested to the 

 writer that the same operation would cut and cleanse India 

 rubber. It was tried, and found completely successful, in all 

 cases, as a labor-saving machine, and indispensable in the 

 manufacture, when the gum is mixed with foi^eign substances. 



COMPOUNDING. 



It is important to observe, first of all, that the sulphur, lead, 

 or other articles that are compounded with the gum, should be 

 pure, and free from acid, otherwise the gases that are generated 

 in heating, will cause the gum to blister ; and when these sub- 

 stances, however pure, are compounded with dissolved gum, and 

 especially with liquid cement, it should be used soon after it is 

 mixed, and when the weather is very warm, or when it is kept 

 in a warm room, within a day or two, otherwise it will ferment, 

 and cannot be vulcanized. Ignorance of these particulars nearly 

 prevented, for a considerable time, any practical applications of 

 the discovery of vulcanizing being made by the inventor. Still 

 greater caution is necessary when camphine or spirits of tur- 

 pentine is used for dissolving the gum, for though it be obtained 

 perfectly pure, yet if it is exposed to the atmosphere, or left to 

 stand for a length of time, it becomes acid and unfit for dis- 

 solving gum-elastic. It was owing to this circumstance that 

 the goods first manufactured in the United States were much 

 worse, and the losses were much greater, than they other- 

 wise would have been ; and a want of proper care with regard 

 to these various particulars, was the cause of many accidents, 

 and much loss to those persons who first engaged in the manu- 

 facture of vulcanized gum-elastic, especially when dissolved 

 gum was used. 



Gum-elastic can be readily mixed or combined with almost 



