137 [ 175 ] 



4. Thedupioa, or double cocoons, are so called, because they con- 

 lain two, and sometimes three worms. They interlace their threads, 

 and make the silk called dupion. 



5. The soufflonsare imperfect cocoons, the contexture of which is 

 loose, sometimes to that degree that they are transparent, and bear the 

 same proportion to a good cocoon, as a gauze to a satin. These can- 

 not be wound. 



6. The perforated cocoons are so called, because they have a hole 

 at one end; for which reason they also cannot be wound. 



7. The calcined cocoons are those in which the worm, after the for- 

 mation of the cocoon, is attacked with a sickness, which sometimes 

 petrifies it, and, at other times, reduces it to a fine ^vhite powder^, 

 without in the least damaging the silk. On the contrary, these co- 

 coons produce more silk than the others, because the worm is lighter. 

 They are to be distinguished by the noise the petrified worm makes 

 when the cocoon is shaken. In Piedmont, they sell for as much more 

 as the others. It is very rare to see a parcel of 25 lb. of them at a 

 time: 6 lb. 3 oz. of these cocoons have produced 1 lb. fine silk, of five 

 and six cocoons. 



8. The good choquette, consists of those cocoons in which the v/orm 

 dies before it is brought to perfection: they are to be known by the 

 worms sticking to one side of the cocoon, which is easily to be per- 

 ceived, when, on shaking it, the chrysalis is not heard to rattle. These 

 cocoons are of as fine silk as the others, but they are to be wound se- 

 parately, because they are subject to furze out, and the silk has not so 

 bright a color, nor is it strong and nervous, 



9. The bad choquette is' composed of defective cocoons, spotted or 

 rotten; many of these cocoons may be wound together; they make 

 very foul, bad silk, of a blackish color. 



To judge whether a cocoon be good, observe if it be firm and sound ; 

 if it has a fine grain, and the two ends round and strong, and capable, 

 of resisting pressure between the thumb and finger. The cocoons ot 

 a bright yellow yield more silk than the others, because they have 

 more gum; but this accounts to the winder only, because all the gum 

 is lost in dying. Pale cocoons have less gum, lose less in winding, 

 and take a better white or pale blue.* 



To the foregoing kinds of cocoons, another is mentioned in recent, 

 French works, and called sattiny. Its tissue is coarse and like flannel, 

 and the surface shines. The silk of this cocoon is bad. 



As it will be useful to know the precise dimensions of a stove and 

 basin used for heating waj,er for cocoons, the following details are 

 given by Mr. Stephenson, of an establishment at Montauban, in. 

 France: Height of the stove from the ground, twenty-two inches^ 

 length of the stove, twenty-nine inches and a half; breadth, twenty- 

 four inches; height of the iron bars for supporting the charcoal fronj 

 the ground, for holding the fire, twelve inches; width of the door, or 

 opening at the bottom of the stove for taking out the ashes., and fcr 



* Ti-ans. Amer Philos. So^-. vol ?. 



