ey | 
for half an hour; only 60 grains of fulphur were diffolved, by 
which I found that this alkali can take up nearly 3 of its weight 
of fulphur in the moift way; I fay nearly, as fome earth re- 
mained with the undiffolved fulphur. With this faturated liver 
of fulphur I precipitated a folution of allum, and found the pre~ 
Ccipitate to amount to 130 grains. Now 8o grains of mere 
mineral alkali can precipitate only 120,8 grains of earth of allum; 
therefore g grains of the above precipitate were fulphur. Yet 
this {mall proportion of fulphur was very vifible in, the earth of 
allum when heated to 500 degrees, by its ftrong yellow colour; 
therefore in. the precipitation of the earth of allum by kelp, in. 
which no fulphur was vifible, the proportion was incomparably 
fmaller, and no deduétion- need be made on that account, 
THERE.are-three methods of: defulphurating kelp, or any other 
alkalino fulphureous compound: The firft is by calcining it in an 
open fire by expofing it to a rapid blaft of air; and for this 
a very ingenious. contrivance was. devifed by my much refpeéted 
friend Mr. Witt1am: Dean. The only inconvenience attending 
it is that much of the fulphur will be converted into vitriolic 
acid, and thus combine with the alkali. The fecond is by fatu- 
rating it with a vegetable acid; and afterwards calcining it, by 
which means the vegetable acid will be decompofed; if this 
method could be cheaply executed it. would be the beft. "The 
third is by faturating a folution of kelp with fixed air: This I have 
endeavoured to effect by putting a folution of two ounces of kelp 
into DoGor Nooth’s machine for impregnating water with fixed 
air; the liquor foon became turbid, and emitted a ftrong hepatic 
fmell ; 
