300 An Tj[fay on Bleaching, 



■of directing the cylindrical glafs veflel, in which torn and 

 patted prints arc put when cleaned, to be inverted on water 

 charged with materials fit for extricating the oxygenated mu- 

 riatic acid gas, his recipe directs the materials to be put in 

 the bottom of the jar itf'elf, which is certainly better. Great 

 accuracy, however, is neceflary in the doles and in the con- 

 dueling of' the procefs, otherwife the texture of the paper may- 

 be deftroyed.] 



Bleaching by the oxygenated Muriatic Acid and Pota/h. 



The fuftbeatino- emanation of the gas has rendered it necef- 

 fary to employ potafh in the liquor; Dut this mixture, though 

 it enabled the workmen to manage the fluffs without incon- 

 venience, occasioned an outlay of money for the alkali, and 

 weakened the deter five quality of the oxygenated muriatic 

 acid. It is a fact well known, that a folution of oxvgenated 

 muriate of potafh does not bleach goods, yet it differs from 

 the oxygenated muriatic acid ley only by having the alkali in 

 it : it is, then, incontestable that the acid liquor lofes its pro- 

 perty of deftroying the colouring matter of vegetables in pro- 

 portion as it is neutralized by potaft). 



Not with (laud ing the truth of this obfervation, it is proper 

 to fay a few words refpecting the method of compofmg this 

 Icy : the proportion of the alkali in general is, 

 8 parts (in weight) of fea fait, 

 60 parts of concentrated fulphuric acid, 

 30 parts of manganefe, 

 20 parts of potafh. 



The fubfequent preparations and manipulations are exactly 

 the fame as thofe I above defcribed : it will however follow, 

 from the obfervation I have made, that the diminution of 

 the detergent force by the alkaline mixture will render a great 

 many more manipulations neceffary ; and if we add a com- 

 parative calculation of the two operations, it will J)e found, 

 without including the expenfe of diftilling the oxygenated 

 muriatic acid, which is the fame in either procefs, there will 

 be a iaving of more than forty-five per cent, beiides the extra 

 manipulations, in not employing alkalies. We here fubjoin, 

 a comparative calculation. 



With Alkali. ' franco 



8 lb. marine fait, at 15 cents, per lb. 12 



60 ditto fulphuric acid, at 65 cents. 39 



30 ditto manganefe, at 20 cents. - 6 



20 ditto potafh, at 75 cents. - 15 



A* 



