696 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



bulk or length by a superabundance of food, which allows the 

 secretion which forms the wool to increase. 



Wool and cotton require an entirely different treatment from 

 flax in spinning ; the fibers of these substances are short, and 

 must be made into a roll before they can be drawn into a threa,d ; 

 they, together with silk, are spun in a dry state ; whereas flax, and 

 all vegetable fibers, require to be moistened during spinning. 

 The wool of sheep, as we now have it, is the product of cultiva- 

 tion ; in their natural state their hair is short, with soft wool 

 near the skin. All quadrupeds inhabiting cold climates have 

 coarse hair, which completes its growth in one year, and then 

 falls off, to be succeeded by a fresh coat. 



But of all known fabrics, silk is the most conspicuous, and it 

 is surprising that men should have advanced so far in civiliza- 

 tion before they discovered that the caterpillar was capable of 

 producing so splendid a material for clothing of endless variety 

 and beauty. 



China was no doubt the first to make use of silk. Twenty-four 

 thousand eggs of the silk moth weigh a quarter of an ounce. The 

 worm lives fifty-four days ; in thirty days of this period it in- 

 creases nine thousand six hundred fold, and during the last thirty 

 days of its life, eats nothing. Seventy pounds of cocoons may be 

 obtained from the consumption of eight hundred pounds of mul- 

 berry leaves ; one hundred and five pounds of cocoons give nine 

 pounds of sj)un silk ; and two pounds of cocoons will produce a 

 thread one million, one hundred and seventy-six thousand feet 

 long. More than one million, six hundred thousand people derive 

 their entire support from the culture and manufacture of this 

 valuable product ; and the silk worm no doubt creates an annual 

 circulating medium of at least $230,000,000. Still, the nature of 

 the silk worm, and the process of producing silk, remained a pro- 

 found secret with the Chinese, and was utterly unknown in 

 Europe until the reign of Justinian, 555 years before the birth 

 of Christ. 



Mr. Seely. — Attention had been called only a few years to the 

 chemical nature of cotton. Gun cotton, when first known, was 

 generally considered valuable as a substitute for gunpowder. 

 This idea has now been abandoned ; but it has certain advanta- 

 ges, which still make it valuable for particular cases, perhaps, 

 for instance, in charging shells. It is unaffected by moisture, is 

 more explosive, is more easily prepared, and the materials may 



