niOhjeSisof the Art of Dying, ^c. 37 ^ 



complicated kind of dying, or callko printings 

 and this knowledge was not confined to them, 

 but was pofleffed by other Eaftern nations. From 

 the Eaft alfo proceeded, to us, Chemiftry her- 

 felfj and, it is highly probable that the art was 

 of great antiquity in that part of the globe; and 

 had arrived at a degree of perfection, of which 

 we have at prefent, no fuitable ideas. To have 

 invented the procefs of printing, in the manner 

 defcribed by Pliny, the inhabitants of India 

 muft, probably have known how to prepare 

 alum*, they muft have been acquainted with the 

 manner of diflblving lead in the vegetable acid; 

 they muft, at leaft, have been acquainted with 

 the component parts of thefe falts ; and they 

 muft have had a knowledge of double eledtive 

 attra<flions. 



In our divifion^ of the various colouring fub- 

 ftances, of the animal and vegetable kiods, we 

 took notice that there are fome, viz. thofe of 

 the third divifion, which not having, of them- 

 felves, a fufficient attraftion for the cloth, re- 

 quire to have an earthy fubftance applied as an 

 intermedium. The requifites in this earth are, 

 that it fhould have a ftrong attraftion for the 

 material to be dyed, and alfo for the colouring 



* The faftltious fait, which is now called alum, was firft dif- 

 covered in the Eaftern j_countries ; but when, where, and by 

 what means, is unknown. 



Bergman's Eflays, vol. I, p. 339. E. tranfl. 



B b 2 principle j 



