176 BLEACHING. 



binding. On this account, the best way is to de- 

 stroy the binding entirely, that each leaf may 

 receive an equal and perfect immersion ; and this 

 is the second process recommended by M. 

 Chaptal. 



" They begin," says he, " by unsewing the book, 

 and separating it into leaves, which they place in 

 cases formed in a leaden tub, with very thin slips 

 of wood or glass ; so that the leaves, when laid flat, 

 are separated from each other by intervals scarcely 

 sensible. The acid is then poured in, making it 

 fall on the sides of the tub, in order that the leaves 

 may not be deranged by its motion. When the 

 workmaa judges, by the whiteness of the paper, 

 that is has been sufficiently acted upon by the 

 acid, it is drawn off by a cock at the bottom of the 

 tub; and its place is supplied by clear fresh water, 

 w^hich weakens and carries off the remains of the 

 acid, as well as the strong smell. The leaves 

 are then to be dried, and, after being pressed, may 

 be again bound up. 



" The leaves may be placed also vertically in the 

 tub ; and this position seems to possess some ad- 

 vantage, as they will be less liable to be torn. 



" With this view, I constructed a wooden frame, 

 which I adjusted to the proper height, according 

 to the size of the leaves I wished to whiten. 



" This frame supported very thin slips of wood, 

 leaving only the space of half a line between them. 

 I placed two leaves in each of these intervals, and 

 kept them fixed in their place by two small wooden 

 wedges which I pushed in between the slips. 



" When the paper was whitened, I lifted up the 

 frame with leaves, and plunged them in cold water, 

 to remove the remains of the acid as well as the 

 smell ; this process I prefer to the other. 



