as ObjeSls of the Art of Dyingy (^c. ^49 



gation of the nature of colouring fubftances, laid 

 the foundation on which the prefent fabric is 

 cre(5led. 



Much room is however ftill left for the im- 

 provement of the art, and I am convinced that 

 it is only by our pra<5lical dyers acquiring chemi- 

 cal knowledge, that it can ever be effecfled, to 

 any great extent. While men do not underftand 

 the grounds on which they (hould proceed, many 

 errors muft arife, many needlefs materials muft 

 be employed, and much expence, which might 

 be fpared, muft be incurred. To promote this 

 defirable end, I fhall, with the permiflion of 

 this Society, lay before them, not only fuch 

 information, as I have extracted from the beft 

 writers on the fubjedl, but fuch fafis as I have 

 been able to colleft, and obfervations which 1 

 have had opportunities of making, tending to 

 form a juft theory of dying ; and efpecially 6f 

 thofe proceffes where mordants are employed. 



The variety which obtains in the facility with 

 which animal and vegetable fubftances attraift 

 colouring matter is a curious fubjecl for inveftj- 

 gation. It is known that fome colouring ingredi- 

 ents which aremoft readily imbibed, and tenaci- 

 cufly held, by Wool, have much lefs efFeft on 

 filk, and are either wholly rejedled, or very 

 (lightly attached to, cotton or linen. Different 

 preparations and mordants, applied under differ- 

 ent 



