22 Mechanical Philosophy. 



but they continued to lie in uncertainty and con- 

 fusion, until 1709, when Mr. Hawksbee, an Eng- 

 lish gentleman, wrote on the subject, and distin- 

 guished himself by the experiments and discove- 

 ries wiiich he announced. He first took notice of 

 the great electric powers of glassy together with 

 a variety of phenomena relating to electrical at- 

 traction and repulsion j insomuch that his writings 

 and experiments form a grand cera in this branch 

 of knowledge. From the time of Mr. Hawkseee^s 

 publication, near twenty years elapsed before any 

 farther discoveries or improvements were sug- 

 gested. 



In 1729, the fundamental distinction between 

 conductors and non-conductors was first ascertained 

 by Stephen Gray, a British philosopher, who 

 had for some time before amused himself with 

 electrical experiments, and w^ho was now acci- 

 dentally led to the discovery of this important prin- 

 ciple. Soon afterwards M. Do Fay, member of 

 the Academy of Sciences at Paris, in repeating Mr. 

 Gray's experiments, unexpectedly perceived, for 

 the first tim.e, that difference in the attractive 

 powers of different bodies, vvdiich he supposed to 

 arise from t^j/o different species of electric fluids, 

 and which he denominated the vitreous and resi- 

 nous electricities. The drawing a spark from the 

 living body was also first observed by this gentle- 

 man, and his companion, the Abbe Nollet. The 

 next person who distinguished himself in this part 

 of science was Dr. Desaguliers, who, though he 

 added but little to the knowledge before possessed, 

 yet made some valuable experiments, and invented 

 some technical terms, such ^s conductor, electric per 

 se, 8(c. which have proved highly convenient, and 

 are still in use. About 1742 electricity began to 

 excite attention, and became the subject of much 

 inquiry in Germany. Professor Boze, of WitteniT 



