ON DYEING REDS ON COTTON. 



289 



industry, which constitutes the base of the employment 

 and trade of the first manufacturing city of the French 

 empire. 



The manufacturers of Rouen employ both fast and false Dyers of 

 colours. I have already imparted to the latter, by thehelp 0Uen * 

 of certain mordants, a degree of richness, lustre, and even 

 permanence, before unknown; which no doubt procured 

 the specimens I sent the honour of being admitted to the 

 exhibition of 1806. 



The class of citizens who are not wealthy, and they are Articles of 

 the most numerous, require clothes of a price proportionate inferior P ric ^ 

 to their circumstances. Besides, the dyeing of inferior 

 colours employs a number of workmen, and yields a profit, 

 that would soon be seized by other towns, if it were 

 despised here. 



But the reputation and wealth of our manufactories are The best dys 

 derived chiefly from the colours called fast, that is to say most im P ort - 

 those that are produced by the process for Adrianople red. 

 These colours have opened a vast field of inexhaustible 

 fertility to the manufacturer. He can now employ in his 

 designs that variety, that happy mixture, that elegant as- and carried to 



sociation, that harmony of colours, which are so pleasing g reat P etfec - 



' ... ° uoru 



to the eye, and so gratifying to the taste of the most fasti- 

 dious. Instead of those peiishable colours, that delighted 

 for a moment, the Indian red, and the extensive series of 

 colours derived from it, as the cherry, rose, violet, lilac, 

 july flower, amaranth, &c, in all their various tints, have 

 little to fear from the most destructive agents, and scarcely 

 yield to the long continued action of air, light, and soap. 



This process therefore is of the highest importance to us; Some man*- 

 but, though it is practised with the greatest success by JJJJJJ'*™ faiI m 

 some manufacturers, others meet with obstacles, that occa- 

 sion failures, which it would be highly useful to be able to 

 prevent. I have endeavoured as far as possible to remove 

 these, and to dissipate the uncertainty attending the oper- 

 ations performed on the cotton intended to receive this 

 colour, by a chemical investigation of them. 



I have the honour now to present to the Institute the Use of sheep** 

 result of my examination into the nature and use of sheep's dung in dy- 

 clung in dyeing Adiiai'Ople red, my object being to impart 



Vol. XXXII, August, 1812. X solid 



