An EJpiy on Bleaching. 301 



As the ley lofes its force by the addition of potafh, this 

 lots may be eftimated at 15 per cent., or 10 f. 80 cents. , 

 which mud: be added to the preceding 72 francs, making 

 icr 82 f. 80 cents. 



Without Alkali. 



f nines. 

 80 lbs. of fea fait, at 15 cents, per lb. T3 



60 ditto fulphuric acid, at 65 cents. 39 



30 ditto manganefe, at 20 cents. - 6 



57 

 The difference between thefe two procefTcs is coflfiderable. 



Of Bleaching with oxygenated Muriates. 



This method was fir ft thought of in Ireland. The fub- 

 ftance employed is the oxygenated muriatic acid combined, aS 

 we have faid, with- earthy or faline bales. Calcareous earths, 

 fuch as lime and chalk, are thofe ufed in general ; magnefia 

 is too dear, and the rarity of barytes and ftrontian will ex- 

 clude them for fome time from our m an u factories. A di- 

 ftilling apparatus of lead, fuch as we have already alluded to, 

 (p. 259,) is employed. A tube /, (fee Plate IV. the lower- 

 molt figure) three inches in diameter, riles from the top of 

 the alembic gg, and proceeds to the bottom of a leaden re- 

 lervoir ?n, capable of containing about 15 gallons, two-thirds 

 of which are filled with water. Another tube n, of the fame 

 dimensions, alfo of lead, the orifice of which is above the 

 level of the water, rifes from the refervoir m 9 and enters the 

 tub 0, ©, in which the liquid oxy-muriate of lime is prepared. 

 This tub muft be large enough to contain twelve barrels, or 

 about 1500 (Englifh) gallons of water: 80 pounds of lime, 

 flaked in the air and well pulverized, is introduced into it : 

 the fides of this tub are furnifhed with fhelves or a grating, 

 q q y, which projects in the infide/while the arms of the agi- 

 tator /, to which a rotatory motion is communicated, move 

 between the (helves, and conftantly ftir the liquor : this dif- 

 pofilion is indifpenfable to prevent the lime from being pre- 

 cipitated before its faturation, and to prefent, by renewing 

 them, the greateit number of furfaces poilible to the action 

 of the acid gas. The ufe of the intermediate refervoir, vi, is 

 to arreft the portion of the muriatic acid gas which efeapes 

 during the commencement of the operation without being 

 oxygenated, and alfo any fulphuric acid which may chance 

 to pal's, and which would hurt the procefs if it were furTered 

 to be introduced into the tub 0, 0, The property which the 



muriatic 



