310 ON ELECTRICAL ATTRACTIONS AND REPULSIONS. 



ducting surface to attract the foil, it will be attracted l>y 

 the moisture of the air. The reflections I shall make on 

 the substance of glass to explain the 4th Experiment will 

 serve to account for the down, which is a nonconductor, 

 acquiring in this instance an affinity for the fluid. 



I do not perceive here any repulsion : for, according to 

 the Author himself, the metallic leaf goes to part with its 

 electricity to the conducting substance. In the electroiner 

 ter with pith balls, that diverge from each other, by which 

 the electrical repulsion is frequently attempted to be 

 proved, these balls separate only because the aqueous va-r 

 pours of the air attract them. This is the reason of the 

 movement of the little pendulum of Henley's electrometer, 

 which I find to be one of the best. In tine, the divergence 

 of all electrometers, as it appears to me, is produced by 

 the attraction of aqueous vapours, or the action of some 

 conducting substance, which attracts leaves and small balls 

 eaturated with electric fluid. 



2d Experiment, 



£d expert- f« Suspend freely to the conductor of an electrical ma- 



chine a fringe of thread twisted together so as to form a 

 tuft ; and the moment you electrify rhe apparatus, you 

 will see all the threads, that were united together, separate 

 from each other, and this to a greater distance in propor- 

 tion as the electricity is powerful." 



Ko repulsion. ' Here the air, as with respect to the electrometer, attracts 

 and separates as far as possible the threads. Every natural 

 philosopher no doubt will agree, that the vast evaporation 

 of water, that takes place from the surface of the globe, 

 must impregnate the atmosphere more or less with aqueous 

 vapour, even in what we call dry weather, and that this im- 

 parts to it a great affinity or attraction for the electric fluid. 

 The circumambient air around the electrical machine, 

 therefore, is that which can most readily effect its union 

 vith this fluid. That which is farther off, having the same 

 tendency, must consequently attract toward it as far as pos- 

 jible every substance saturated with it. Hence it follows, 

 that, the more of the fluid every thread has imbibed, fhe 



mete 



