148 
SELECTED ARTICLES. 
flame, and leaves no residue. I call this matter melanic acid, 
on account of its color. I prepared the melanate of silver in 
the same manner as the salicylate of silver. It fell down as a 
black, heavy powder. I preferred this salt for analysis, to as- 
certain the composition of melanic acid. It is as follows: 
0.500 melanate of silver gave 0.088 water and 0.500 car- 
bonic acid. 
0.200 of the same left 0.096 silver. 
The composition of melanate of silver, from this data, is: 
Theory. 
C 20 
764.40 
27.63 
27.67 
H 8 
49.92 
1.71 
1.95 
0* 
500.00 
18.18 
18.82 
AgO 
1451.61 
52.48 
51.56 
2765,93 
100.00 
100.00 
The free acid gave from — 
I. 0.350 acid, 0.127 water, and 0.722 carbonic acid. 
II. 0.325 acid, 0.674 carbonic acid. 
Theory, Experiments. 
I. 
II. 
o° 
764.40 
58.16 
57.05 
57.40 
49.92 
3.80 
4.01 
a 
O 5 
500.00 
38.04 
38.91 
u 
1314.32 100.00 100.00 
To ascertain what had become of the other elements of the 
salicide of potassium, I examined the solution obtained by 
washing the carbonaceous mass with water. 
It is perfectly neutral to test paper. It leaves on evapora- 
tion a white saline residue, which is deliquescent, and burns 
on platinum foil, yielding carbonate of potassa. It is not pre- 
cipitated by the salts of lime or baryta, or by acetate of lead. 
The nitrate of silver and protonitrate of mercury occasion a 
white flocculent precipitate. These experiments indicate 
acetate of potassa. To obviate all uncertainty, I mixed a part 
