L294 
fmell ; after the fulphur had fubfided I drew off the liquor, and 
with one half of it precipitated a folution of allum. No hepatic 
fmell was now perceptible, and the precipitate amounted to 40 
grains. I dare not fay that this great increafe of power in the 
alkali was intirely owing to the defulphuration, but fome part 
undoubtedly was; yet the quantity of fulphur I could colle& was 
very inconfiderable, and mixed with coal duft. Kelp:may alfo be 
defulphurated by nitre, as fhall hereafter be fhewn. According 
to Do@tor Watfon, 30 ounces of kelp afforded hith 12 ounces of 
cryftallized mineral alkali, confequently 1 eunce would afford 
,4 of an ounce, that is 192 grains, of which +, that is =38 grains, 
muft have been mere alkali. His kelp might have been better 
than that I ufed; but it is impoflible that his alkali was pure, as 
mineral alkali, when mixed with fucha quantity of common falt 
as is in kelp, can never be thoroughly feparated from it, but by 
proceffes which he certainly did not ufe, namely, by precipitat- 
ing a folution of filver in fpirit of nitre, eftimating the quantity 
of luna cornua, and afterwards decompofing the cubic nitre, or 
by faturating the alkali with diftilled vinegar, and diffolving the 
neutral falt thus formed in fpirit of wine, which leaves the common 
falt behind. 
Srrancrorp KELP. 
Tuts was fent to me by my worthy friend Mr. BravcGHatt. 
It was much denfer, lefs porous, and in appearance approached 
more to that of a vitrified mafs than Cunnamara kelp; it was at 
leaft equally fulphureous. ‘The folution of one ounce of it preci- 
pitated only 9 grains of earth of allum, and this earth was much 
more 
