On a saline Substance from Mount Vesuvius. 427 
gj. Carbonate of soda, and oxalate of potash, and solu- 
tions of magnesia, clay, copper, iron, and zinc, either had 
no effects, or extremely slight ones. 
k. Solution of sulphate of silver produced a white curd- 
like precipitate. 9°35 grains of this salt (the weight of the 
insoluble matter being deducted) afforded 1°05 grain of 
slightly melted muriate, or chloride, of silver. This preci- 
pitate was equally produced after the salt had been made 
strongly red hot, so that it was nut owing to a portion of 
sal ammoniac. 
l. Tartaric acid, and muriate of platinum, occasioned 
the precipitates in its solution which indicate potash. 
m. Nitrate of lime did not form any immediate precipi- 
tate in a dilute solution of it; but in a short time, numerous 
minute prismatic crystals of hydrate of sulphate of lime 
were generated. 
n. Nitrate of barytes poured into a solution containing 
9°8 grains of this salt afforded a precipitate, which after 
being ignited weighed 12°3 grains. The filtered solution 
erystallized entirely into nitrate of potash mixed with a few 
shomboids of nitrate of soda. 
o. Some of this salt finely pulverized was treated with 
alcohol. This alcohol on exhaling Jeft a number of minute 
cubic crystals, which proved. by the test of nitric acid, to 
be muriate of soda. Prussiate of soda and iron caused a 
red precipitate of prussiate of copper in this alcoholic solu- 
tion. 
' p. The solution of this salt afforded, by crystallization, 
sulphate of potash in its usual forms, and some prismatic 
crystals of hydrate of sulphate of soda. 
g. To discover what had occasioned the precipitate with 
galls, (7) since copper bas not this quality, a portion of 
this salt, which bad been recovered by evaporation from a 
filtered solution of it, was ade red hot in a platina cruci- 
ble. On extraction of the saline part by water, a very small 
quantity of a black powder was obtained. Ammonia dis- 
solved only part of it, which was copper. The rest being 
digested with muriatic acid, and prussiate of soda and iron 
added, a fine Prussian blue was formed. 
r. From several of the foregoing experiments, it ap- 
eared that no sensible quantity of any of the mineral acids, 
Dosides the sulphuric and muriatic, existed in combination 
with alkali in this volcanic salt. But Mr. Tennant, whose 
many and highly important discoveries have su greatly con- 
tributed to the progress of chemical science, having de- 
fected disengaged boracic acid amongst the volcanic pro- 
Ps 2 ' ductions 
s 
