380 Mr. Henrfs CMfiderations on different Materials ^ 



It may alfo hje worthy of remark, that cotton, 

 having but a weak attraftion for colouring mat- 

 ter, requires that it fhould be prefented under 

 every advantage : and the Dijon Academicans 

 having proved, that the mineral acids are de- 

 ftrudtive of the aRringent principle, in which the 

 colouring matter of thofe fubftances requiring 

 a bafis feems to refide ; this property, added to 

 others, may be a reafon for their rejeftion,, and 

 for the preference given to the acetous acid. 



Having thus given an account of the various 

 preparations that are generally ufed for wool, 

 filk, and cotton, and of the bafes, applied for 

 the reception of the colouring matter, let us next 

 take a view of the particular preparatory operati- 

 ons, praaifed in the procefs for dying the Adrian- 

 ople or Turkey red on cotton ; and to thefe alfo 

 add a detail of the procefs itfelf. It is proper to 

 premife, that all the wooden vefiels employed 

 fhould be made of deal, or of fome white wood, 

 free from aftringent matter j and that the mod 

 convenient quantity for operating on, in propor- 

 tion to the ingredients ufed in the feveral opera- 

 tions, is fixty-fix pounds of cotton. 



From fixty pounds of Alicant barilla, a ley is 

 drawn, by means of foft water, amounting to fixty 

 gallons— and then, by the pouring on of frelh 

 water, a fecond ley is formed, meafuring forty 

 gallons— after this, a third ley is alfo extrafted 

 ■ from 



