Silk Manufacture: 181 



would be more quick and certain in its operation, as well as pro- 

 ductive of less injury to the texture of the silk. When the oven 

 is used, the cocoons are placed in long shallow baskets, filled to 

 within an inch of their tops, and covered, first with paper, and 

 then with a cloth wrapper. The heat of the oven wherein the 

 baskets are disposed has not been more precisely defined, than 

 that it should be very nearly that of an oven from which loaves of 

 bread have just been taken after being baked. The worms are ex- 

 posed to this heat during an hour; and on their being withdrawn, it is 

 ascertained by the examination of chrysalides, taken from the cen- 

 tre of each basket, whether the vitality of the worms is destroyed. 

 Those chosen for examination having been, from their position, 

 the least exposed to the heat, it is fairly presumed that if these be 

 dead the whole are equally destroj^ed. On their removal from 

 the oven, the baskets are wrapped in woolen cloths or blankets, 

 and piled on each other. If the baking has been properly con- 

 ducted, the blankets will soon appear profusely covered with mois- 

 ture, and if this should not be seen, the baking has been either ex- 

 cessive or insufficient. If too great, the worms and cocoons will have 

 been previously so much dried as to leave no further moisture to 

 transude; if too little, the heat has not sufficiently penetrated to 

 distil the liquor which the chrysalides contain, and the worms, 

 in that case, will not be deprived of vitahty. 



' It is obvious that very great nicety is required to limit the de- 

 gree of heat to the exact point that will kill the chrysalides, and 

 it is of great importance that this point shall not be exceeded, as 

 the silken filaments would by such means be injured. For this 

 reason steam would doubtless be much more frequently used, if 

 any simple apparatus were introduced for the purpose. Where 

 this agent is now employed, its efficiency is so limited that the 

 operation is troublesome and the result uncertain. 



' A large wooden vessel is provided, into which boiling water is 

 poured to the depth of two feet. This vessel has within it a 

 wicker hurdle, entirely covering the water, and supported about 

 one inch distant from its surface. The bottom of this hurdle is 

 provided with a coarse porous cloth, easily penetrable by steam: 

 on this the cocoons are placed, and are covered well over to con- 

 fine the heat. When the water has become so cool that it no 

 longer emits a body of steam, it must be changed for other boil- 

 ing water; and it is considered necessary to continue this steam- 

 ing process for two hours, before the destruction of the chrysalides 

 can be considered certain. If steam were differently applied, a 

 few minutes would suffice for perfecting this object. The cocoons, 



