400 BULLETIN OF THE BUSSEY INSTITUTION. 
XII. Several clean lumps taken from a new supply of furnace-coal, at 
the Bussey Institution, were ground to a moderately fine powder, and 
20 grammes of the powder were boiled with milk of lime; 0.00004 
gramme of ammonia was obtained, or 0.0002 %. 
XI. A quantity of small fragments of coal (‘‘ slack ’’), from the heap 
whence No. XII was taken, was sifted through very fine sieves, and 20 
grammes of the dust were boiled with milk of lime. The first 250 ce. of 
distillate contained 0.0005 gramme of ammonia. On further distillation, 
ammonia continued to come off slowly and constantly ; 0.00005 gramme 
ammonia was found in every fifty cubic centimetres of the distillate, until 
six such portions had been collected. But the next fifty ec. portion of 
distillate contained much less ammonia (0.00002 gramme), and the pro- 
cess was then interrupted. All told, there was found in this experiment 
0.00082 gramme of ammonia, or 0.0041 o%. 
On boiling 20 grammes of this coal-dust with alkaline permanganate 
of potash and with milk of lime, an amount of ammonia was obtained 
that appeared to be much larger than the quantity just stated, but the 
precise amount was not determined. 
20 grammes of the same sample of coal were shaken together with 
500 ce. of pure water, at intervals during two days; and 50 cc. of the 
clear, supernatant liquid were then tested for ammonia by boiling with 
milk of lime. There was found 0.00001 gramme, or 0.0005 % of the 
coal. 
XIV. Several large, clean lumps of furnace-coal, taken from the same 
heap as No. XI, after other loads of fresh coal had been mixed with it, 
were broken up, and a fair sample of the fragments was powdered ; 20 
grammes of the powder boiled with milk of lime gave 0.00011 gramme 
of ammonia, or 0.00055 o&%. 
It is to be observed that the coal whence samples Nos. XI to XIV 
were taken differed from that of the other samples in that it had been 
mined a year later. It was examined, moreover, a month or two after 
it had been mined, instead of six or eight months, as in the other in- 
stances. 
Some idea of the significance of the figures above recorded may be 
gained by contrasting the amounts of ammonia in anthracite with the 
amounts of ammonia that have been found in soils. Thus, while it 
appears, from the foregoing experiments, that 100 grammes of anthra- 
cite ordinarily contain from 0.0002 to 0.0008 or even 0.00566 gramme 
of ammonia, the experiments of Knop and Wolf,* made upon five dif- 
ferent kinds of soils, show no more than from 0.00012 to 0.00087 
gramme of ammonia for 100 grammes of auhydrous earth. 
* Knop’s “ Lehrbuch der Agricultur-Chemie,” Leipzig, 1868, 2. 86. 
