302 An EJ/qy on Bleaching, 



muriatic acid has of eafily combining with water, facilitates 

 its condenfalion by the intermediate refervoir. 



By drawing out a little of the ley from time to time one 

 may know when the liquor in the tub is faturated. When 

 it fuffers the lime introduced to be precipitated, the operation 

 is terminated. This oxy-muriate of lime is drawn off from 

 its depofit, and it is then fufficiently concentrated to be em- 

 ployed for breaching when diluted with three times its volume 

 of water. 



This liquor is found to be preferable to the oxygenated 

 muriatic acid and potafh. At the jxreat bleach-fields in Ire- 

 land, four leys of potafh are. applied alternately with four 

 weeks expofure on the grafs, two imoiernqna in the oxygen- 

 ated muriate of lime, a ley of potafh between the two, and 

 the expofure of a week on the grafs between each ley and 

 the immerfions. During fummer, two leys and fifteen days 

 expofure are fufficient to prepare cloth for the action of the 

 oxygenated muriate; then three alternate leys, with immer- 

 fions in the liquor, will be fufficient for complete bleaching: 

 nothing then will be neceffary but to wind the cloth through 

 the fulphuric acid. 



Bleaching by calcareous Sulphuret. 



In all the proceffes for bleaching which I have hitherto 

 defcribed it is leen that potafh acts a diftinguifhed part, either 

 as an auxiliary or a principal agent. To find a deterfive fub- 

 itance which might be a fubltitute for it, was an object of 

 the utmoft importance. Kirwan fufpeeted that it would be 

 found in the fulphuret of lime, and his opinion was con- 

 firmed by Higgins. 



Repeated trials, and the moft evident fuccefs, have proved 

 the advantage of employing this method, and the poftibility 

 of bleaching completely by condenfing the muriatic acid with 

 the fulphuret inftead of potafh. The procefs with the ful- 

 phuret of lime is attended with fome advantages peculiar to 

 itfelf. In the firft place, quicklime and crude fulphur are 

 matters which can be procured at a cheap rate, especially 

 when the latter enters into the mixture in fmall quantity : 

 feeondly, their combination is effected in the eafiefl: and moft: 

 expeditious manner, and may be comprehended and executed 

 by any common workman : the application being then made 

 by immerfing the cloths cold, there is a complete faving of 

 fuel, and no rifk is incurred either from the ignorance or negli- 

 gence of the workman, as the ley does no injury to the ftuffs. 



The fulphuret of lime is prepared in the following manner: 

 Take 4 pounds of finely pulverized fulphur, 20 pounds of 



flaked 



