i eS 
trench, and when it is full the fire is difcontinued *. I believe 
alfo that wafhing the fea weed in frefh water, to carry off the fea 
falt that adheres to it, would be ufeful. 
_To defulphurate kelp, Abbé Mazeas recommends projecting 
on it while in a red heat + of its weight of nitre; but this 
procefs feems too expenfive to be practifed in the great. 
2dly, This alkali is found native in Agypt and feveral parts 
of the Ruflian empire, and perhaps may be cheaply imported. 
3dly, Common falt may be decompofed after Mr. TuRNER’s 
method, by trituration with litharge, as the calx of lead here 
employed is afterwards converted into a yellow pigment. This 
method is very beneficial. 
I nave alfo contrived another procefs for decompofing com- 
mon falt. The particulars of my experiment were as follows : 
ft, I rendered the common falt pure by adding to its folution 
a folution of mineral alkali until all the earthy matter was de- 
pofited. 
2dly, To a folution of three ounces of this purified falt in nine 
ounces of water I gradually added a faturate folution of 4,75 
ounces of fugar of lead, both hot, until the folution of lead 
{carce excited any whitenefs in that of ‘the common falt. After 
one 
* Mem. Paris, 1767. 
