202 
ACTION OF CERTAIN CHEMICAL REAGENTS. 
Carbonate of potassa occasioned a slight effervescence with 
l-250th, or l-310th real acid. 
For Phosphoric acid. — Brazil wood paper, and paper stain- 
ed with red cabbage, detected l-10,000dth of anhydrous phos- 
phoric acid. 
Litmus paper was immediately reddened by l-10,000dth, 
and after some hours by l-30,000dth phosphoric acid. 
Peculiar reagents for various acids. 
For free Sulphuric acid. — A concentrated solution of 
chloride calcium, occasioned a precipitate, after some hours 
in a solution containing l-130th real sulphuric acid. 
A solution of acetate of lead, gave a precipitate with 
1-50,000 real acid. 
A solution of chloride of barium, gave a precipitate with 
l-75,000dth. 
For combined Sulphuric acid. — Acetate of lead produced 
a precipitate in a solution of sulphate of soda containing 
l-36,000dth of acid. 
Chloride of barium in a solution of the same salt, containing 
l-45,000dth acid. 
For Nilric acid. — By means of hydrochloric acid, and 
gold leaf, l-240th of nitric acid, specific gravity 1.32, was de- 
tected ; the gold leaf was dissolved in 24 hours. 
For Phosphoric acid. — Acetate of lead produced an im- 
mediate precipitate with*l-10,000dth anhydrous acid, and with 
l-20,000dth, after remaining for half an hour. 
Lime water produced exactly the same effect. 
Chloride of barium did not occasion a precipitate in less 
than l-10,000dth. 
For Jlrsenious acid. — Lime water in excess produced a 
precipitate in a solution, containing l-4000dth of this acid. 
Ammoniacal solution of oxide of copper, detected 
l-8000dth. 
Sulphate of copper and ammonia, detected l-12,000dth. 
The two last reagents occasioned precipitate in still more 
diluted solutions, but the precipitates did not possess their 
characteristic green color. 
