292 CHYMISTRY APPLIED TO AGRICULTURK, 



boiler ; as soon as it is seven or eight inches in depth, the 

 fire may be kindled. 



The steam arising from the boiling ley spreads itself 

 through the whole mass of linen, penetrating into all its fold- 

 ings through the openings in the metallic pipes, so that the 

 whole will imbibe a high degree of heat. The boiling of the 

 ley may be continued during three or four hours. 



It may be feared that the bottom of the boiler may be 

 burned by being kept dry from the evaporation of the ley ;. 

 but there is no danger of this, as almost the whole of the 

 steam which arises is condensed and returns again into 

 the boiler. If it be judged necessary to guard against the 

 possibility of this evil, a copper pipe of an inch in diameter 

 may be attached to the bottom of the boiler, and extended 

 to the outside of the wall of the fire-place, and to this may 

 be fitted a glass tube, by means of which the height of the 

 liquor may always be estimated. If by chance it should hap- 

 pen that the evaporation is not sufficiently compensated for 

 by the quantity of condensed fluid returned, the fire can be 

 checked, and a new quantity of boiling ley thrown into* 

 the tub. 



When the heat has subsided, — that is to say, in eight or 

 ten hours after the firo baa been extinguished, — the linen i& 

 taken out and carefully washed. 



In the year 1802, I had two hundred pair of sheets,, 

 which were taken from the Hotel-Dieu, washed, and was 

 assured by the sisters of I'Hopital, that they were cleaner 

 and better bleached than by the ordinary process. The ex- 

 pense of the washing, of which an exact account was kept, 

 was less than three sevenths of the expense of the common 

 method.* 



When articles made of very fine linen are to be steamed, 

 a solution of soap should be used in preference to one of an 

 alkali. 



Cotton yarn can be bleached entirely by the above process. 

 If it should happen that any portion be less white than the 

 rest, a few days' exposure in a field will render it perfectly 

 white. 



Messrs. Cadet-de-Vaux and Curaudau have exerted 

 themselves much in improving this process, and still more 

 in causing it to be used, both on account of its simplicity 



* This apparatus has been established at the Barridre des Bon&^ 

 HommeSy in the thread manufactory of the Messrs. Bawens. See-* 

 the 38th Vol. of the £nnales de Chimie, page 291. 



