Or tHE SILK-WORM. 35°55 
If. Toknow whether a cocon be good or not you muft ob-- 
ferve if it be firm and found, or not, if it has a fine grain,, 
and if the two ends are round and {trong. The cocons 
of a bright yellow yield more filk than the others, becaufe 
they contain a greater quantity of gum; but the advan- 
tage accrues to the winder only, becaufe all this gum is 
loft in the dying. For which reafon, as well as for cer- 
tain colours they take better, the pale filks are preferred, 
becaufe having lefs gum they lofe lefs in: boiling. 
In the number of cocons that are bought, there ought 
to be neither foufflons, nor perforated cocons; hecaufe 
the feller is obliged to keep them. apart and to fell them 
as fuch; notwithftanding which, you may always reckon 
on half profit of thefe forts that remain with the others, 
and if to thefe you add the dupions and choquette, you 
may calculate them at ten per cent. 
The cocons of the mountains are better than thofe of 
the plain; there is a greater quantity of white amonett 
them. Tis true they are not fo large as-thofe of the plain, 
but the worm, at the fame time, is proportionably lefs. 
The reafon of which is, that the air of the mountains be-- 
ing fharper, the worm labours with greater vigour.. They, 
fucceed, likewife, better in the dry plains than in the damp 
and. marfhy parts, becaufe the leaf is more nourifhing. 
Five or fix days after the cocon has been detached from 
the branches, it is your bufinefs to prevent the birth of 
the worm, who would, otherwife, pierce through the fhell, 
and thereby render the cocon:ufelefs.. To prevent which 
you muft put your cocons in long fhallow bafkets, and 
fill them up. within an inch of the top. You then cover 
them with paper and a wrapper over that. Thefe bafkets 
are to be difpofed in an oven, whofe heat is as near as can 
be that of an oven from which the bread is juft drawn 
after being baked. After your cocons have remained 
therein near an hour, you muft draw them out, and to fee 
whether all the worms are dead, draw out a dupion from 
the. 
