SILK-WORMS. 
339 
grains, it will appear that the moths have lost, in 
four days, 1,610 grains in earthy, liquid, and 
aeriform substance. 
If the 91,800 eggs, obtained from 180 moths, 
yielded an equal number of silk-worms, and that, 
well managed, they each in time formed a cocoon, 
from the eggs produced by the above-mentioned 
lilb. of cocoons, we should obtain 3821bs. eight 
ounces of cocoons, which the following year would 
yield eggs sufficient to produce 97,5371bs. eight 
ounces. 
7. Facts relative to the Buildings and Utensils. 
To make the laboratory of the silk-worms si- 
milar to their native climate, they must be enabled 
to live in it perfectly free from all moisture ; the 
temperature should neither be too hot nor too 
cold, and above all, they should never be exposed 
to sudden transitions from one state of atmosphere 
to another ; the air should always circulate gently. 
A warehouse, a cellar, or any other low, shady, 
close place, is best calculated for the preservation 
of the leaves during two or three days, provided 
it be cool, damp, and shut from air and light. 
The utensils employed to rear silk-worms, are 
constructed so as to spare time and expense, and 
for the better management of the silk-worms and 
the eggs at all times. The interest of the culti- 
