Silk Manufacture. 235 



some, are nevertheless necessary to possess a thriving bird. 

 When wild, all birds require water, and this is also necessary to 

 the canary. If a vessel of snow be put into a cage, they will flut- 

 ter against it with the utmost delight, even in the most severe 

 winters. They are bred in immense numbers, both for com- 

 merce and amusement, in England, France, Tyrol, Germany, and 

 other countries. 



CABINET CYCLOPEDIA,. 



SILK MANUFACTURE. 

 NO. XI. 



Electric Properties of Silk. ' The discovery that silk is 

 an electric, or a non-conductor of electricity, originated in one of 

 those fortunate accidents to which science has been indebted for 

 many of her most valuable discoveries. This fact it was which 

 first led to the beautiful disx;losure of the distinction between elec- 

 trics and non-electrics. 



'In 1729, while the knowledge of electrical phenomena was yet 

 in its first infancy, Mr. Gray, after performing many interesting 

 experiments, succeeded in conducting the electric fluid, excited 

 by friction in a glass tube, through a perpendicular distance of 

 many feet, by causing one end of a piece of iron wire or pack- 

 thread to communicate with a glass tube, and the other end with 

 an ivory ball. Pleased with his success, he became desirous of 

 conducting the fluid horizontally; but this experiment failed at 

 the time through the mode of his attempting it, which was by car- 

 rying, his line over a packthread cord, suspended for the purpose 

 across the room. Through this material, the electric stream es- 

 caped, and the ivory ball was, in consequence, no longer found to 

 be excited. 



' Mr. Gray having communicated to a friend the ill success 

 which had attended this attempt, was advised to suspend the con- 

 ducting line by silk instead oi packthread ; there being no other 

 reason for this advice than the greater fineness of the former. 

 Acting upon this suggestion, their first experiment was made 

 in a large matted gallery; a line, the middle part of which was 

 of silk and the two extremities of packthread, was fastened across 



