60 BULLETIN OF THE BUSSEY INSTITUTION. 
more strongly heated than others. A roasted material, thus obtained, 
may of course represent a variety of products, corresponding to the sev- 
eral temperatures at which they were produced; but on some accounts 
such complexity would be advantageous for experiments like those now 
in question, since, if any one among the various products were useful as 
plant food, the fact would be exhibited by the crops, and the chances of 
finding such an one would probably increase with the number of the 
products. 
As was the case with the roasted sheepskin, the whole of the roasted 
leather obtained was ground together to a fine homogeneous powder, 
from which separate quantities, sufficient for each jar, were weighed out, 
to be mixed with the corresponding quantities of sand. 
E. With 1300 grms. Berkshire sand and 18 grms. fine clippings of 
worn and washed, thin cotton cloth. The shreds of: cloth were mixed 
with the sand by alternate layers. Besides the chemicals enumerated in 
the tables, this set of jars, excepting Nos. 4 and 5, were watered once at 
the beginning of the experiments with a solution of sulphate of lime. 
F. With Berkshire sand alone. These jars, like the foregoing set, 
were watered once with sulphate of lime. 
G. With 1200 grms. Berkshire sand and 7 grins. chopped Nassau 
sponge. ‘The sponge was washed with chlorhydric acid and with water, 
dried and cut into small pieces, which were mixed with the sand in the 
jars, by alternate layers. 
H. With 1000 grms. of powdered anthracite. It may here be said that 
one purpose of experiments H, I, and J, was to ascertain, if possible, the 
source of a certain small amount of assimilable nitrogen that had been 
previously noticed in the ashes of anthracite.* The true explanation of 
this question was discovered afterwards, as has been explained on page 
401. 
I. With 1100 grms. Berkshire sand and 180 grms. anthracite powder. 
J. With 1100 grms. Berkshire sand and 180 grms. roasted anthracite; 
i.e., powdered anthracite that had been heated to 250° (C.) in a tin cup 
sunk in sand. When thus heated, the anthracite gave off a small amount 
of moisture; but there was no evidence of any change that could have 
unlocked any of the nitrogen in the coal, or have increased the assimila- 
bility of any of its constituents. 
The foregoing experiments were made in the autumn of 1874, three 
buckwheat seeds having been planted in each jar on the 14th of Novem- 
ber. The seeds were watered with rain-water at first; but, after the plants 
appeared, each jar was watered with the solution of some one special 
chemical substance, as stated in the tables below. The solutions of these 
chemicals were made with rain-water, and were of the following strengths: 
Sulphate and phosphate of potash, 0.25 grm. to the litre; nitrate of lime, 
1 grm., and nitrate of potash 1.25 grms., to the litre. In the present 
series of experiments, there were two more jars in each set than in the 
other series. For jars Nos. 5 and 6 of the present series, the two kinds 
* See Bussey Bulletin, 1. 62. 
