122 METHOD OP BLEACHING PAPER. 



$■•■ 5. The receiver. It is compofed I. of an external vcffcl, 



covered with plates of lead well foldered together, and pro- 

 vided near its bottom with a cock 6, to draw off the liquor 

 when prepared. 2. Another veffel, 7, likewife covered with 

 plates of lead within and without. This fecond tub is inverted 

 in the firft to contain the gas in proportion as it is difengaged, 

 and to keep in contact with the water of the receiver, that 

 portion of gas which had not time to be difiblved, in palling 

 through that fluid. 



There is a hole, 8, in the upper part of this fecond vefleJ, 

 It ferves to fuffer the common air to efcape when water is 

 firft poured into this receiver, and it is afterwards clofed with 

 a ftopper of lead or cork, covered with paper, foaked in 

 ftarch, and fattened to the cork by a piece of cloth or bladder, 

 before the operation began. 

 Vertical fcaion. Fig. 2. Vertical feclion of the apparatus. 



Fig. 3. Elevation of the apparatus. 



The difpofition of the furnaces about the receiver, and the 

 circular form of the receiving veifels, was rendered neceftfary 

 by the local circumftances of the laboratory in which our ope-, 

 rations were carried on. In otfier circumftances fquare vek 

 fels might be employed, and all the furnaces might be ranged 

 in a right line under a common chimney. 



One thoufand litres of water are placed in the receiver, 

 holding in folution fifty kilograms of white purified and cal- 

 cined potafli. 



When the difengagement of gas is effected by the muriatic 

 acid, the materials are ufed in the following doles : 



Oxide of manganefe - - ? - - - 24 kilograms 



Muriatic acid at 20 degrees 1 68 



of denfity according to the > — 



earometer of Baum6, 92 



which makes for each of the eight diftilling veflels llf kilo-t 

 grams of materials. 



Charging and The operation is begun by charging the receiver with 1000. 



dirtillation. litres of alkaline water, after which the aperture 8 is clofecj 

 with its ftopper well luted. Each mattrafs is then placed 

 in its fand-bed ; and pulverized manganefe is introduced. 

 The muriatic acid is poured upon the manganefe, and the 

 ftoppers into which the tubes of communication pafs, are 

 duly placed. The juncture is luted with paper foaked in 



ftarch. 



