BULLETIN OF THE BUSSEY INSTITUTION. 59 
several other substances, viz., upon simple unroasted sole leather, and 
sheepskin, upon cotton cloth, sponge, and anthracite, both natural and 
roasted, and upon simple sand or earth to which no leather or the like 
had been added, were tried at the same time with those upon the 
roasted leather. , 
The experiments were all made in wide-mouthed glass jars (preserve 
jars), in the glass-house or conservatory which forms a part of the Bussey 
Laboratory, and were conducted in the same general way as the experi- 
ments previously described in this Bulletin, Volume I. pages 54 and 253. 
In the first set of experiments, the leather or other material was mixed 
with Berkshire sand.* Ten sets of jars, each set consisting of seven 
pieces, were charged as follows: — 
A. With 1300 grammes Berkshire sand and 20 grms. of the shavings 
of sheepskins. These shavings came from the flesh side of skins that 
had been tanned in sumac. They were in the air-dried state when taken 
for these experiments. ‘The shavings were cut into fine shreds before 
being put into the jars. The jars were charged with alternate layers of 
the shreds and the sand. It may here be remarked that the very bulky 
character of the sheepskin and of several of the other materials inter- 
fered somewhat with the conduct of the experiments. With such 
voluminous materials, it is difficult to charge each jar precisely like the 
others of its set, and in watering the plants, afterwards, special care has 
to be exercised in order that all the jars may be kept properly moist. 
B. With 1300 grms. Berkshire sand and 20 grms. of roasted sheepskin. 
The product here in question was obtained by heating shreds of sheep- 
skin to 160° @ 180° (C.) in a tin cup sunk in sand at the bottom of an 
iron pot. A thermometer was kept in the cup, and the sheepskin was 
stirred continually until the whole of it had become brown and friable. 
The roasted product was ground to powder in a mortar, and the weighed 
quantity destined to each jar was thoroughly mixed upon a plate, with 
the 1300 grms. of sand, before putting the mixture in the jar. 
C. With 1300 grms. Berkshire sand and 40 grms. sole leather. The 
leather was new and clean. It was cut into fragments as large as small 
peas, and mixed with the sand in the jars, layer by layer. 
D. With 1300 grms. Berkshire sand and 40 grms. roasted sole leather. 
A quantity of small cubes of the leather, such as were mentioned above, 
under C., were roasted at temperatures ranging from 180° to 200° (C.) or 
more, in a tin cup sunk in sand as explained in paragraph B., or until 
the whole of the leather was black and brittle, and a good many of the 
pieces had become puffed out and swollen, like parched corn. 
It was found to be much less easy to regulate the temperature of the 
roasting of sole leather than of sheepskin. In order to obtain the pecu- 
liar swollen or parched effect just mentioned, the temperature of the 
sand bath had to be raised so high that it was less easy to control it than 
was the case at lower temperatures, so that some bits of the leather were 
* Compare Bussey Bulletin, 1. 59, and 2. pp. 11, 17. 
