[ 175 j 114 



It may be regarded as a general rule, that the worms ought not to 

 touch one another. 



Quantity of leaves consumed by Silkworms in tJieir different ages. 



The result of a most exact calculation is, that the quantity of leaves 

 drawn from the tree, employed for each ounce of eggs, amounts to 

 1,609 lbs. 8 ounces, divided in the following manner: 



Two hundred and forty pounds eight ounces weight, lost in refuse 

 picked from the leaves, and by evaporation, make up the gross weight. 



Facts relative to the cocoons containing the healihy chrysalis: dis- 

 eased chrysalides, and dead chrysalides. 



When the cocoons are perfectly formed, the)'' diminish, in the four 

 first days, three quarters per cent, each day; the other days, the dimi- 

 nution is very trifling. 



Seven and a half pounds of cocoons, containing healthy chrysalides, 

 yield eighteen ounces of pure cocoons; which will give eight ounces 

 of silk when spun. This proportion of silk to cocoons, may vary ac- 

 cording to the ill or good management of the worms. In the unfavor- 

 able year 1814, Dandolo obtained fifteen ounces of silk from seven 

 and a half pounds cocoons, and thirteen ounces from the same quanti- 

 ty of refuse cocoons: we find one pound of coarse flos to nineteen of 

 cocoons that can be spun, and four ounces of flos to eleven ounces of 

 spun silk. 



About 506 feet of the single thread, or fibre of silk from worms of 

 three casts, weigh one grain. 



The cocoon of this worm yields ^-^^so g^'ai'is of silk; and, if we 

 make an average calculation, we shall extract about 1 1 ounces of silk 

 from 3,000 cocoons, weighing 7§ pounds. The same cocoon jaelds 

 1,166 feet long of the single fibre. In an ounce of this spun silk will 

 be found a length of 291,456 feet. 



The cocoon of the worm of four casts, yields ^^^'^ grains of silk, 

 because there are about 11 ounces of spun silk drawn from ISOO co- 

 coons, weighing Ih pounds. This cocoon yields 1760 feet of spun 

 silk; 421 feet 8 inches of silk from a cocoon of a worm of four casts 

 weigh a grain: 11 ounces of silk are drawn, on an average, from 750 

 cocoons, weighing Ih lbs. This cocoon consequently gives about 

 3,885 feet of spun silk; an ounce of this silk is 242,880 feet long. In 

 this are not included the first down taken oif the cocoon, nor the flos. 



