On the Ufe of Sulphuret of Lime iri Bleaching. 253 



It would give me much pleafure if I could ftate any thing on the fubjea: of enquiry refped- 

 ing the method of difengaging the colouring matter of piece-goods from its combination with 

 alkali. But the affinities of the former muft be nearly unknown to moft chemifts, becaufe, in 

 general, they can have few opportunities of fubjefting it to experiment. There can be little 

 doubt, however, of its total deftruaibiiity by lieat with accefs of air. If, therefore, the faturated 

 lees were evaporated to drynefs, and then incinerated, with or without the conta61: of vegetable 

 fuel, I conclude, of courfe, that the alkali might be profitably recovered. 1 am aware that the 

 Ikill and refearclies of my corrcfpondent render it unnecefiary for me to remind him, that there 

 arefome contrivances for doing this, with little expenceof fuel, in the treatife of Pajot des 

 CharmeSjOf which a tranflation was lately publiflied. 



- With regard to the qucftion concerning water-courfes, it cannot be treated in general, 

 without including the quantity of water delivered in a given time as one of the data. I do 

 not know that pra6lical men have paid any confiderable attention to the lofs which is fuftained 

 by the frjdlion of water againft its channel or bed ; but fliall take a future opportunity of rc- 

 fuming this fubjeiSl:. W. N. 



V. 



On Sulphuret of Lime, to be ujed as a Suhjlitute for Potajh in Bleaching with th0 Oxy- 

 genated Muriatic Aid. By Mr. Willi AM Hicgins, M.R.I. A. and Profejfor of 

 Chemijlry and Mineralogy at the Repofttory of the Dublin Society.* 



OiNCE I had the honour of being appointed chemiftto the linen board, which is now more 

 than three years, I have allotted a confiderable portion of my time and attention to the inveftiga- 

 tion of the principles of that fcience, applicable to the art in which I am thus more particularly 

 interefted. It appeared, that, until potafli could be difpenfed with, we muft for ever remain 

 in the power of foreign nations as to our ftaple commodity. Obferving alfo, that all the late 

 improvements in bleaching were exclufively confined to one obje£l — that of imparting 

 oxygen to the cloth, in a fafe and expeditious manner, but that there had been no effort made 

 to fuperfede the neceffity of potafli, by far the moft expenfive and uncertain article employed 

 by the bleacher, and for which he is entirely dependent upon foreign markets} I directed my 

 attention chiefly to difcover a fubftitute for potafti ; which, provided it fliould be of Irifli 

 produ<3:ion, though it might be equally expenfive, I conceived would be of the utmoft na- 

 tional importance. Imprefled with thefe ideas, I undertook a feries of experiments with 

 that view. 



To enumerate the many difappointments and failures I experienced during my invefti- 

 gation would be endlefs, and an unnecefiary intrufion upon my reader. Knowing, from 



* From his " Effay on the Theory and Praftice of Bleaching," juft publilhed at Dublin, and forwarded to 

 me by the refpeftable writer of the preceding article. 



Vol. III. — September 1799. LI an 



