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BLEACHING. 165 



CURING OR TANNING, 



Commonly known as the acid gas process. This has been 

 employed since a patent was first obtained for it by the writer, 

 by generating the gas with a mixture of nitric and muriatic acid, 

 and immersing the article in it while the acid is in a heated 

 state ; but latterly the process has become much more efficacious 

 and practicable for general use, by first dipping the goods in 

 diluted nitric acid, and afterwards in chloride of lime and water: 

 this method renders the effect uniform without danger of scorch- 

 ing the fabrics ; beside, it is much less expensive than the former 

 method. 



CLEANSING THE GOODS. 



PERFORATING. 



The improvement made in gum-elastic fabrics by the simple 

 process of perforating, will cause them to be extensively used for 

 many articles for which they would not otherwise answer, on 

 account of their confining perspiration and being uncomfortably 

 warm. Two methods of perforating are practiced, one of which 

 is accomplished by means of calenders set with needles, through 



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