544 



THE INTELLECTUAL RISE IN ELECTRICITY. 



the difference between them is greater. After such touch 

 there is no spark between either of them and C, because 

 the electrical fire is reduced to the original quantity. If 

 they touch while electrizing, the equality is never de- 

 stroyed, the fire only circulating." B therefore is posi- 

 tively or plus electrified, and A negatively or minus. 



The fire may be circulated, says Franklin, and "you 

 may also accumulate or subtract it upon or from any body 

 as you connect that body with the rubber or with the re- 

 ceiver (tube), the communication with the common stock 

 being cut off." 



Franklin's chief concepts, therefore, are first, the normal 

 state of equilibrium of the common stock of electrical fire 

 in all bodies; second, that this equilibrium may be dis- 

 turbed, so that a body, by reason of the disturbing action, 

 may have fire given to it or taken away from it; and third, 

 that, after the disturbing action ceases, the reaction is 

 transference of the fire back to the original state of equi- 

 librium. The fluid analogy readily suggests itself. The 

 common stock of electrical fire may be represented by the 

 atmosphere. If air be accumulated above atmospheric 

 pressure in a vessel, it will escape therefrom into the 

 aerial ocean until the pressure without and within the ves- 

 sel is equalized. If air be exhausted from a vessel, the 

 atmosphere from without will rush into that vessel agaii 

 until the pressure outside and the pressure inside are th< 

 same. 



The staid people of Philadelphia, however, do not flock 

 to Franklin's house to listen to his theories, but to witness 

 his experiments; and, indeed, he and his colleagues are 

 as alive to the marvelous aspect of it all as Bose himself. 

 The electrical fire leaps "like lightning," writes Franklin, 

 around the gilt ornaments on china plates, or on the sides 

 of books, or around the mirror and picture frames. Philip 

 Sing contrives little pasteboard wheels which are driven 

 like wind-mills when brought near the rubbed tube. 

 Franklin lights candles just blown out, by drawing a spark 



