[ 88 ] 
at the fame temperature, was ,960. Volatile alkali is always 
lighter than water, when perfe@tly cauftics. Alkaline air, as well 
as marine acid air, from its extreme volatility, feems difpofed to 
unite moit copioufly with the firft portions of water. That thefe 
become lighter by uniting with it feems to depend on the 
elafticity of the alkaline air, which the attractive force that 
unites it te water is incapable of entirely repreffing. 
Vitriolic Acid. 
We are informed by the moft refpeCtable authorities that vi- 
triolic acid has been obtained fo ftrong as to be more than twice 
as heavy as water, but by what procefs I remain ignorant. I have,” 
though perhaps miftakenly, fufpe@ed that fuch acid was not 
pure, but owed its great weight to felenite, vitriolated lead or vitri- 
olated alkali, which it contained. I found the fpecific gravity of com-" 
mon vitriolic acid increafed from 1,845 to 1,892, by diffolving 
in g ounce meafures of it 960 grs. of vitriolated vegetable alkali. 
Six pounds of common vitriclic acid (fp. gr. 1,842) were diftilled 
until 3134 grs. came over ; what remained was concentrated to 1,849. 
Four pounds cf this concentrated acid were heated until the bottom 
of the retort and the liquor itfelf appeared red, and were expofed to 
this heat for above half an hour, during which time copious 
white 
* This is not the cafe with the aerated volatile alkali; this liquor, obtained accord. 
ing to the fame difpenfatory, was found, in two experiments, to be 1,042. 
