*54 -d' 1 mf a y m Bleaching* 



Thofe who wilh to acquire information refpe&mg the art of 

 ioap-making may coni'ult the excellent work of Darcet, Pel- 

 letier, and Lievre, publiflied a few years ago by the order of 

 the French government. 



Sulphuret of Lime. 



Lime and fulphur are two fubftances which nature prefents 

 to us with profusion. They combime perfectly together. 

 Their union is called fulpburet of lime, and they then form 

 a very a&ive detergent matter. Kirwan firft obferved that 

 faline fulphurets, or the combination of an alkali with fuW 

 phur, might be employed with advantage in bleaching on 

 account of their deterjive properties, and even fupply the 1 

 place of alkalies. What Kirwan propofed was executed by 

 Higgins in Ireland; and by analogy of reafoning he was led 

 to the difcovery of the detergent power of fulphurets of lime. 



In whatever manner theie fubftances are combined, the 

 refult is always the fame; either in the dry way, by fufing 

 them together, which produces a very ftrong and very folid 

 fulpburet ; or by uniting quicklime and fulphur, and pouring 

 over them eight or nine times their weight of water; the 

 heat alone of the lime while flaking will be fufficient to com- 

 bine them : or, in the laft place, by following the procefs of 

 Higgins, which confifts in boiling together flaked lime and 

 fulphur. The laft method is that which ought to be pre- 

 ferred for bleaching. 



The liquor which refults from this union of water, lime* 

 and fulphur, is liquid fulpburet of lime: it is of a dark yellow 

 colour, and has a harm ityptic tafte; it emits an odour fome- 

 whatfimilar to that commonly perceived in fulphur and flaked 

 lime. This emanation, however, is not of a noxious nature 

 like that of the oxygenated muriatic acid. 



Liquid fulpburet of lime lofes its colour by expofure to the 

 air, andfpeedily abforbs the oxygen of the atmoiphere. Thefe 

 properties deferve the attention of the bleacher, as they will 

 ihow the advantage of employing this folution as frelh as 

 poffible, left the quality of it fhoulctbe hurt; and they explain 

 a part of the principles, according to which liquid fulpburet 

 of lime exercifes an action in the art of bleaching. 



From the above observations the following practical prin- 

 ciples may be deduced : 



Sulphuret of lime, of all the alkaline compounds, is the 

 moil powerful folvent of the colouring matter of flax ; cauftic 

 potaCh is the next ; then cauftic foda ; then common potafti ; 

 and, in the laft place, common foda. Sulphur, if employed 

 pure, itains cloth a little; but the ftains may be eanly re- 

 moved 



