154 Silk Manufacture. 



All these minute directions may perhaps appear frivolous; but 

 it is only by an unceasing attention to these and the like minutiae, 

 that any tolerable success can be secured. When all the previ- 

 ous cares and labors of an establishment have been satisfactorily 

 accomplished, if the hedges be not well formed, are irregular; or 

 too thick in any parts, so as either to impede the circulation cf air, 

 or too far to limit the space in proportion to the number of worms, 

 ill success will be sure to follow. Instead of the proper number 

 of fine single cocoons, many will be double, others imperfect or 

 soiled, and even some of the silkworms will be suffocated before 

 the completion of their labors. 



' It is essential, in every age of the worms, to attend to the reg- 

 ulation of temperature in their apartments; and at no time is this 

 more necessary than while they are forming their cocoons. If, 

 at this time, they are exposed to much cold, they desist from 

 their labors. Should the balls be sufficiently thin, the insects 

 may be discerned, either quite inactive, or moving very slowly. 

 On the temperature being raised, they will immediately resume 

 their work with renewed activity, and will once more desist, if 

 the cold be again allowed to exert its influence. After they have 

 remained inactive from this cause for a short time, they put off 

 their caterpillar form, and assume that of the chrysahs, without 

 having sufficient energy to complete their silken covering. 



'The fifth volume of the transactions of the Society for the En- 

 couragement of Arts, ^c. contains a letter upon this subject from 

 a gentleman, who relates, that in the summer of 1786 he had suc- 

 cessfully reared to their full growth more than thirty thousand silk- 

 worms, when at the beginning of July, and just as they appeared 

 about to spin, a chilling north-east wind set in, and many of the 

 worms became chrysalides, without attempting to spin. On the 

 examination of these, it appeared that the glutinous matter in their 

 silk reservoirs had become so congealed by the cold, as to resem- 

 ble strong tendons, both in appearance and tenacity; which suffi- 

 ciently accounted for the inability of the insects to draw forth the 

 silk in filaments. Thousands of the worms changed in this profit- 

 less manner daily, until at length, the survivors being removed in- 

 to an apartment artificially warmed, they immediately applied 

 themselves to the performance of their usual functions. It is de- 

 sirable that while silkworms are in the act of spinning, the tem- 

 perature of their apartment should be maintained as high as 70 

 degrees, and it is at the same time equally important that free 

 ventilation should be secured. 



' The opinion has been very generally entertained that violent 

 noise distui-bs, and injuriously aiFects the worms, and that any 



