BULLETIN OF THE BUSSEY INSTITUTION. 399 
plain, that the coal contained some soluble salt of iron, and that the 
ammonia which the lime set free had been previously held back by the 
acid of the iron salt. It must, indeed, often happen that anthracite, and 
especially the dust of anthracite, is so highly charged with sulphate of 
iron that no ammonia can be expelled from the coal by mere boiling with 
water. But, on boiling with milk of lime, with the proper precautions, 
the ammonia in the coal is readily made manifest. 
VI. Several lumps of the stove-coal from the bin whence Nos. II, 
IV, and V were taken, having been ground to powder in a drug-mill, 
10 grammes of the powder were put in a flask with some water free from 
ammonia, and distilled until no more ammonia came forward; 0.00002 
gramme of ammonia was found in the distillate, — that is to say, 0.0002 %, 
of the coal. No additional ammonia was obtained in this case on boiling 
with milk of lime. But 10 grammes of the powdered coal, boiled with 
alkaline permanganate of potash, gave 0.000035 gramme of ammonia, 
VII. 20 grammes of coal-dust from a bin in my own dwelling-house, 
on being boiled with pure water, gave 0.00031 gramme of ammonia, or 
0.0015 % of the weight of the coal. An attempt to boil the residual 
liquor with milk of lime failed through the foaming-over of the liquid. 
VIII. Selected, clean lumps of furnace-coal from the bin No. I were 
washed with water free from ammonia, and reduced to a coarse powder: 
100 grammes of the powder, distilled with pure water in a flask, gave 
0.00011 gramme of ammonia; and as much more was obtained on distil- 
ling the residual mixture with milk of lime. The evolution of the am- 
monia from the mixture of lime and coal was very slow, and was not, in 
fact, completely finished when the experiment was brought to a close. 
The total percentage of ammonia found in this case was 0.00022. 
IX. 550 grammes of powdered lump-coal from bin No. I, percolated 
with three litres of pure water, gave 0.0018 gramme of ammonia, or 
0.000327 9; and no additional ammonia was given off on boiling with 
milk of lime. 
X. A hard, glassy lump of coal, very compact and difficult to break, 
taken from bin No. I, was reduced to powder, and 10 grammes of the 
powder were distilled with pure water; 0.00004 gramme of ammonia was 
obtained, and an additional faint trace came over on boiling the residue 
with milk of lime. The per cent of ammonia in this case was 0.0004. 
10 grammes of fine powder from this hard lump of coal, on being 
boiled with an alkaline solution of permanganate of potash, that had 
been carefully boiled to expel ammonia, yielded 0.00008 gramme of am- 
monia. 
XI. A lump of coal that was somewhat rusty upon its surface, taken 
from bin No. I, was reduced to powder, and 20 grammes of the powder 
were distilled with pure water; 0.000035 gramme of ammonia was ob- 
tained, or 0.000175 %- No additional ammonia was obtained on boiling 
with milk of lime. 
