139 [ 175 3 



manner by a fact recorded by Aldini,* which is, that, in Piedmont and 

 in Lombardy, the gummy cement of the cocoons is so easily soluble, as 

 to require the water to be heated only to 60° or 66° of Reaumur, (168*', 

 181° of Fahrenheit,) while the cocoons spun in the south of Italy, and 

 particularly in the Papal territories, require a heat of 80° of R., (212° 

 of F.) owing to the greater tenacity and solidity of the gum. 2d, The 

 stateof the cocoon, as regards itsfirmness, influences theheatof the water, 

 as shall presently be mentioned. Experiments can alone, therefore, de- 

 termine the various degrees of heat requisite for the water in different 

 places, and for the several varieties of cocoons, and even for different 

 parcels of cocoons of the same sort. As this is a point connected with 

 the success of the operation, it affords another argument for the use 

 of the thermometer, in order to ensure it, and to prevent the delay and 

 trouble which will ever ensue from guessing at the heat of the 

 water, by dipping the finger in it. Our own sensations are very 

 inaccurate tests of the heat of the water; the use of the thermometer, 

 besides saving much time and trouble to the spinner, will ensure an 

 evenness of thread, and perfection to the whole operation.! 



The perforation of the cocoons by the moths, destroys the continuity 

 of the thread, and thus spoils them for reeling. They must, therefore, 

 be either reeled off, before the moths come forth, or after the worms 

 have been killed: the means of doing this, are, by exposing them to 

 the steam of boiling water, or to the heat of an oven. But as it is a 

 fact, well established, that cocoons reel more readily, and that the silk 

 is of a superior quality, when obtained without their having been sub- 

 jected to either of these expedients, every exertion should be made to 

 reel them as soon as proper, after the cocoons have been formed. ;;: 

 When the business is conducted upon a large scale, it may be impossi- 

 ble to do this; in which case, the moths may be prevented from coming 

 forth at their usual time, by placing the cocoons in a cold vault, cellar, 

 or ice-house, as formerly mentioned on the authority of the Abbe Sau- 

 vage.§ 



Practical men are divided as to the best mode of killing the chrysa- 

 lis: some preferring that by steam, and others that by the heat of an 

 oven. — Both methods shall be described. 



The academy of Nismes deemed it so important to ascertain the 

 best mode of killing the chrysalis, as to institute a set of experiments 

 on the subject, in the year 1809: and they came to the conclusion, 

 that the steam of hot water effected the object best, without injuring 

 the quality of the silk. Six ounces of white cocoons were submitted 



•Rechcrchcs, 8s.c. &c. p. 23. 



■J- A mercurial thei-mometer, as already said, chap. G, should be preferred, for those 

 made with spirit of wine are seldom accurate. 



:^ It is the general practice, in Connecticut, to reel off the silk, as soon as possible af- 

 ter the cocoons have been formed, and without kilhng the insect by either of the means 

 mentioned. 



^ Sec chap. 1, at the close. — If placed in an ice-house, the box containing them 

 must be wiVi covered to prevent the absorption of moisture. 



