SILK-WORMS. 
329 
When the proprietor, therefore, has grown 
228 pounds of leaves from the mulberry tree, he 
has contributed to the production of 1 j pounds 
of spun silk, and some ounces of the coarse floss, 
as we shall show presently. 
The proportion between the spun silk drawn 
from the cocoon and the cocoon itself, may vary 
according to the ill or good management of the 
worms. 
In the year 1814, which was unfavourable, my 
cocoons yielded me about 15 ounces of very fine 
silk from 7 a pounds of cocoons ; I even obtained 
13 ounces from 7x pounds of the inferior refuse 
cocoons. 
The proportion between the weight of the 
cocoons containing the healthy chrysalis which can 
be spun, and that part called the coarse floss which 
cannot be spun in the same manner, is, on an 
average 19 to 1 ; that is to say, we find one 
pound of coarse floss to nineteen of cocoon that 
can be spun. 
What I have stated shews that the weight of 
silk floss and chrysalis, proceeding from a given 
quantity of cocoons, is not equivalent to the 
weight of the cocoon itself. The reason of this 
is, that there are two other substances contained 
in the cocoon ; one which the silk-spinners work 
up and sell at a low price, and another which, 
