MOTH. 
2v3l 
degree of heat as to kill the inclosed chrysalides; a 
few oiil}^ being saved for the breed of the following 
3^ear. The Moth, when hatched, is a very short- 
lived animal; breeding soon after its exclusion, 
and when the females have laid their eggs, thejg 
as well as the males, survive but a veiy short 
time. 
The length of the silken fibre or thread drawn 
by the silkworm in forming his ball, is computed 
by Monsk Isnard, a French author, who wrote on 
the subject of the Silkworm in the seventeenth 
century; to be six English miles in length. This 
computation however appears to be a greatly ex- 
aggerated one. The length indeed may be sup- 
posed to differ considerably in different silk-balls, 
but in general will be found far short of what is 
stated by Isnard. According to Boyle, as quoted 
by Derham, a lady, on making the experiment, 
found the length of a ball to be considerably 
more than three hundred yards, though the weight 
was only two grains and a half. The Abbe La 
Pluche informs us that of two balls one measured 
nine hundred and twent3Mour feet, and the other 
nine hundred and thirty. It may be proper to 
add, that the silk throughout its whole length is 
double, or composed of two conjoined or aggluti- 
nated filaments*. 
The general history of the manufacture of Silk 
•* In the Encyclopaedia Britannica we are informed that the 
length varies in different coccoons from 200 to 1200 ells, and 
that in general we may calculate the production of a coccopn 
from 500 to 600 ells in length. 
