of the Acid of Borax. 65 
Being exposed to the air, the blackish colour became lighter, 
and inclining to grey. When digested in sixteen parts of dis- 
tilled water, in the usual temperature, for two days and a half, 
it did not all sink to the bottom ; and, after being digested with 
heat for twenty hours, it was not entirely dissolved : that part 
which sank, was of a blackish brown. More water was then 
added, and it was made to boil for two hours; it was after- 
wards placed upon a paper filter, (the weight of which was 
previously ascertained,) and edulcorated with boiling distilled 
water, till at last a proportion of twenty-six parts of water to 
the substance had been used. After all the fluid, «, had passed 
through, and the filter, with the residuum, had been dried in a 
heat of 212 0 , for an hour and a half, the residuum, (3, weighed, 
exclusive of the filter, nineteen grains. 
Exp. xxiii. The fluid, «, obtained by Exp. xxi. was suf- 
fered to evaporate gradually, and yielded three drams and ten 
grains of a white transparent salt. 
Exp. xxiv. This salt (obtained by Exp. xxm.) was put into 
a small retort, and exposed, in a crucible filled with sand, to 
an open fire. It became of a blackish-brown colour, yielded 
some sublimate, a, (about five grains,) a small portion of fluid, 
b, and a blackish-brown residuum, c, which grew lighter in co- 
lour, on being exposed to the air. 
Exp. xxv. The fluid, b, (of Exp. xxiv.) smelt like marine 
acid, and precipitated nitrate of lead. 
Exp. xxvi. The residuum, c, (of Exp. xxiv.) by the addition 
of some water, became whiter, and was dissolved ; more water 
having been added, it was digested with heat, by which the 
matter was dissolved. The solution being afterwards filtered, I 
MDCCXCIX. K 
