284 



COMPARISON OF DIFFERENT KI^'DS OF ALlTM. 



Art. I. ComparisoJi of the effect ■<: obtained in dj/cing with the 

 alums of Rome, Bouviert LiegCj Javelle, and Curaudau. 



Comparative The materials we employed in operating with these five 

 w'^ol'^ilk II- ^^ums were wool, silk, thread, and cotton. Each of these 

 f»en, and cot- we subjected to the preliminary preparations adopted in the. 

 *^"* most celebrated dyeho^ises. Aware of the extensive use of 



With printed Cotton for printed goods, and that Roman alum i.>. emp'ioyed 

 couons. exclusively for all their delicate colours, we were desirous of 



making some trials, that would enable iis to decide upon this 

 subject. We then had recourse to Mr. Davilliers, who rea- 

 dily, and with the greatest politeness, made a trial of our five 

 alums in his manufactory. The patterns he was so obliging 

 as t6 send us agreed very well with our results; but as the 

 unequal application of the mordant might with some plausi- 

 bility have been objected to us, we endeavoured to obvinte 

 this by adopting another method, that used in dyeing piece 

 goods. 



Mr. Berthollet, jun., who has already distinguished himself 

 in the science and in its application to the arts, particularly 

 ■with respect to printed calicoes, which he has studied with 

 great care in the tine manufactory of Jouy, had the civility 

 to come and direct us in this important part of our labour, 

 and assist us in all the researches we made on this subject. 

 List of expert- Each of the experiments that compose this article was 

 ments. made with all the five alums. 



Woollens. 



Exp. 1. Weld yellow. 



2. Cochineal. 



3 & repeated. IMadder. 



4. • • Kermes. 



5. Archil. 



T/iread. 

 6. Weld yellow. 



Cotton Thread. 



,7. Weld yellow. 



H.* Madder. 



Exp. 9. Sumach. 



Calicoes. 



10, - . . Weld yelKow. 



11. JMadder. 



12 ,.,,,. . .Sumach. 

 Silks. 



13. ;.Weld. 



14. . . .V . ,. .Crimson, 



Silks xoith the acetates produced 

 from the fixe alums. 



lo. .Weld.- 



By 



