ACTION OP CERTAIN CHEMICAL REAGENTS. 201 
12 and 13. Containing l-50,000dth to l-60,000dth iodine 
blue, with a shade of violet. 
14 and 15. Containing l-80 } 000dth to l-100,000dth of io- 
dine, the upper stratum violet blue, the under stratum violet. 
16. Containing l-120,000dth iodine, the upper stratum vio- 
let, the under stratum rose color. 
17. Containing l-150,000dth iodine, the whole precipitate 
rose color, with a shade of violet. 
18 and 19. Containing l-200,000dth to l-250,000dth io- 
dine, rose color, the upper surface only with a shade of 
violet. 
20 to 22. Containing l-300,000dth to l-400,000dth iodine, 
the whole precipitate of a rose color. 
23 to 25. Containing l-450,000dth to l-550,000dth iodine, 
the upper stratum of the precipitate was slightly rose color, 
the under stratum was white. 
The action took place immediately on the addition of the 
starch, as far as No. 19. The following numbers required 
some period to elapse first ; it required some hours in the 
solution of l-500,000dth to l-550,000dth, before any effect 
was produced. 
II. The sensibility of reagents on acids. 
For Sulphuric acid. — Specific gravity 1.829. Containing 
75.83 per cent, real acid. 
Syrup of violets did not detect less than l-250th sul- 
phuric acid of the above specific gravity, or 1-3 10th real 
acid. 
Paper stained with Brazil wood, was acted upon by 
l-10,000dth orl-12,500dth real acid. 
Paper stained by tincture of red cabbage, was reddened by 
l-15,000dth, or l-18,750th real acid. 
Paper stained by logwood, was changed to a golden yel- 
low color, by l-50,000dth or l-52,500dth real acid. 
Paper stained by litmus was immediately reddened by 
l-20,900dth or l-25,000dth real acid, and after some hours 
was slightly reddened by l-50,000dth or l-62,500dth real 
acid. 
vol. VII. — no. in. 26 
