184 Silk Manufacture. 



Cocoons lose in weight about seven and a half per cent, in the 

 course of ten days by the desiccation of the chrysalis: to those, 

 therefore who sell their cocoons previously to reehng, it is an ad- 

 vantage to dispose of them as soon as gathered. In one thousand 

 ounces of perfect cocoons, the chrysahdes weigh eight hundred 

 and forty five ounces, the envelopes cast by the worms on be- 

 coming chrysalides four and a half, and the pure cocoon one hun- 

 dred fifty and a half ounces. Thus each healthy cocoon, as it is 

 gathered, contains more than the seventh part of pure cocoon; but 

 the quantity of reeled silk obtained, seldom averages more than 

 one twelfth in weight of the gathered cocoons. Mayet reckons, 

 that if they are of superior quality, ten pounds of cocoons will pro- 

 duce one poimd of silk; but that it more generally requires eleven 

 or twelve pounds as gathered, to yield that quantity. The same 

 author likewise estimates two hundred and fifty cocoons to weigh 

 one pound: count Dandolo found that two hundred and forty of his 

 made up that weight. 



' If no loss be sustained either in hatching the eggs or in rearing 

 the worms, it is possible to obtain from each ounce of eggs one 

 hundred and sixty -five pounds' weight of cocoons: whatever 

 less in weight is derived from this quantity of eggs indicates the 

 exact amount of loss and damage sustained. In some parts of 

 Italy, where the mode of management is very defective, only forty- 

 five pounds of cocoons are obtained from each ounce of eggs: 

 the average quantity is about one hundred pounds. Count Dan- 

 dolo usually acquired on his estabhshment, from this weight of 

 eggs, about one hundred and forty pounds of fine picked cocoons, 

 in addition to the coarse floss with which they are surrounded. 



' In the year 1790, the Society for the Encouragement of Arts, 

 S)'c. adjudged their gold medal to Mr. Salvator Bertezen, for his 

 having produced five pounds' weight of silk from worms reared 

 in England. This gentleman professed to have a superior breed 

 of worms, and that his manner of managing them was also better 

 than that usually followed. The above quantity of silk, which 

 was wound in seven to nine fibres, was said to be the produce of 

 twelve thousand worms. This fact was much controverted at 

 the time, and the quantity was deemed excessive with reference 

 to the number of worms; but there now appears to be little reason 

 for doubting its correctness, as the proportion very nearly agiees 

 with the recorded experience of count Dandolo. 



'This nobleman gives many elaborate calculations in his volume, 

 the results of some of which may be found interesting. Accord- 

 ing to his experience, about ninety-seven and a half pounds of 



