114 
THE ART OF REARING 
The average length of the silk-worms, which 
was six lines after the second moulting, is be- 
come, in less than seven days, above twelve 
lines. 
The weight of the insect has increased fourfold 
in the same period ; after the second moulting 
610 worms made an ounce, now 144 only will 
complete that weight. 
It has been sufficient during this age to open 
the ventilator, the door, and even the windows, 
when the weather was still and fine, so as to lower 
the temperature by a degree only. 
In the damp close days, a light wood-fire, in 
the fire-place, renews the air by drawing a cur- 
rent, without fear of injuring the interior at- 
mosphere. 
During this age, it never happened to me to 
experience the exterior temperature, although 
higher than the interior, to be beyond the pre- 
scribed limits. 
4. Rearing of the Silk-worm in the Fourth Age. 
In this age, the worms proceeding from five 
ounces of eggs should occupy a space of about 
412 feet square, which should be distributed in a 
manner similar to that practised in the former 
age. 
The temperature of the laboratory should be 
from 68° to 7 1°. 
