4>N ELECTRICAL ATTRACTIONS AND REPULSIONS. $()t) 



pcjra'lsive power of Newton * ? Accordingly 1 took up the 

 fittest modern treatise on electricity, and at the article " Of 

 Repulsions and Attractions," I found six experiments, 

 which are adduced to prove, that this attraction and repul- 

 sion are alternate. I believe, that a double affinity natu- 

 rally explains this alternate movement; and I am per- 

 suaded, that the more we simplify our theories, to account 

 for natural phenomena, the nearer we approach the truth. 



1st experiment of Mr. Libes, on attractions and repul- 1st experiment 

 sions, in his new Dictionary of Natural Philosophy, vol. I. ^e^Jac.^' 

 p. 351. tions and re- 



" Rub with the hand a glass tube, so as to render it per- pli sicfns ' 

 ceptibly electrical. Let fall on this tube a bit of foil, 

 down, or any other light body ; it will be attracted, a»d 

 suddenly repelled by the tube. If in this last state of re- 

 pulsion we follow it with the tube, it will fly off with ra- 

 pidity in a given direction ; but if it meet in its course with 

 another conducting body, that is not electrified, it returns 

 immediately to the tube, and afterward suddenly separates 

 from it ; so that if it hung freely suspended by a silk thread 

 between the tube and the foreign body just mentioned, it 

 would fly alternately from one to the other." 



It is known, that metal has a considerable affinity for the Accounted for 

 electric matter: and it is this affinity, that attracts it to- Jjj? W * O0n 

 ward the tube, the latent electricity of which is not merely 

 excited by the friction, but probably some has been at- 

 tracted from my body to its surface by the same cause; it 

 being drawu toward it, to acquire as much as it can of this- 

 excited fluid. If, while it is in this state, there be any 

 substance near, that has likewise an attraction for the same 

 fluid, and this affinity be sufficiently strong to overcome 

 the gravitation of the foil, it will attract it, seize in its turn 

 the electric fluid, and convey it to the ground, which is 

 equally greedy of it. If the intensity of the foil be still 

 sufficient, to carry it anew toward the tube, these move- 

 ments will continue to alternate, till the attraction of gra- 

 vitation exceeds that of electricity. If there be no con- 



* Optics, quest. Si : of Theory of the £arth Vy Mr. Delametherie, 

 vol. 111. par, 1314. 



4 ducting 



