\ 



47b Neo) Method of Ikaching Coilonis 



grammes (about 800 French pounds, or 880 avoird.) of cotton. The denfity of the ley is 

 in general about two degrees, (qu. by what inftrument ?) After the cotton is properly 

 difpofed in the boiler, the cover is put on, and fcarcely any iflue left for the vapours dif- 

 engaged by the heat, in order that they may acquire a more confiderable degree of heat, 

 and re-a£t with increafed force upon the cotton. When the digefter is charged, the fire 

 is lighted in the furnace *, and the ley fubmitted to a gentle ebullition from twenty to thirty- 

 fix hours. It is then left to cool, the cover is taken olT, the cotton carefully waftied, and 

 expofed in the bleaching ground for two or three days, by fpreading it on frames during 

 the day, and fpreading it on the grafs at night. Thus the cotton acquires a beautiful de- 

 gree of whitenefs ; and if by accident feme portions of the (kains fliould remain unbleached, 

 they are replaced in the boiler, and fubjefted to a fecond operation, or otherwife they are 

 left in the field for feveral days longer. Thefe (hades in the bleached cotton are the confe- 

 quence of its not having been completely and equally impregnated with ley ; but they may 

 alfo proceed from too clofe preflure in certain parts, at the time of (lowing it in the 

 boiler. When the ley is fuppofed to be exhaufted by ebullition, the boiler is uncovered, 

 and the cotton wetted with an additional quantity of the folution of foda j for unlefs this 

 precaution is taken it may eafily burn. 



From thefe particulars it would be eafy to form a notion of the ceconomy of this procefs, 

 by calculating the price of the articles, and the time employed in the operation, if there 

 were not a more fimple method of eftimating its advantages, namely, the low price at 

 which cotton is bleached in all the manufaftories where this difcovery is pradifed. In 

 the fouth of France, where it is now generally adopted,- cotton is bleached at the rate of 

 about eight francs, for forty kilogrammes, (or rather cheaper than a penny a pound.) 

 This procefs was brought from the Levant, a (hort time after we had obtained the method 

 of producing the Adrianople red. It was reduced to praftice, but hitherto kept fecret, 

 under the name of blanchiment a lafumce, (vapour bleaching.) 



Extra£l from the Bulletin of the Philomailc Society. 



This procefs has been employed with the greateft fuccefs by Bourlier, at Bons- 

 Hommes, near Paris. 



The EngU(h, who never neglefl an opportunity of improving their manufadures, made 

 trial of the procefs of Chaptal, as foon as they received information of it. It has com- 

 pletely fucceeded, as appears by the following extract of a letter from a man of fcience at 

 London f . 



" A new method of bleaching has juft been tried at Balynah, and has completely fuc- 

 " ceedcd. The principle of the procefs appears to have been publi(hed by a French 



* The conftruftion here dcfcribed is fora fire of pitcoal ; but if wood be ufed, the dimenfions of the 

 .■fire-place mull be different. In the latter cafe the grate would be ufelefs, a»d the bottom of the veffel too 

 far from the fire.— Delametherie. 

 t The extraft is in French, from which I retranflate. — N. 



" chemift. 



