290 Mr. HenrysConftderations on different Materials^ 



liable to be made ; fimilar praftices are purfued, 

 where the cafes differ effentially; and improve- 

 ments are attempted at hazard, and often on falfe 

 principles. 



Though it may not be granted, that in the 

 fcouring of the feveral materials, which are to 

 be fubjeded to the art of the dyer, their tubular 

 pores are enlarged, or even divefted of any matter 

 which obftrudls them; yet it will not be difputed 

 that the intention of thefe procefles, is to re- 

 move, an oily or a refinous matter which 

 inverts the fibres, and fills up the interftices of 

 the filaments ; either rendering the material lefs 

 white, or leffening its attraflion for water, and 

 for the colouring matter, intended to be applied. 

 For the more brilliant colours, in order that 

 they may be exhibited in their greateft luftre, 

 the fcouring and bleaching is generally carried 

 to fuch a degree, as only to be Ihort of injuring 

 the texture; and the material always fufFers a 

 lofs of fubftance. 



In the preparation for the Turkey red, the 

 cafe feems to be different. No bleaching is 

 allowed ; and the firft operation of the procefs is 

 of a kind, that is rather likely to add to the 

 weight, than to fubtrad any thing from it. The 

 cotton is boiled in a mixture of barilla, or im- 

 pure mineral alkali, oil, and animal excrement. 

 Were the fole intention of this operation to 

 fcour the cotton, or, as the dyers phrafe is, to 



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