Prof. Daniell 07i Voltaic Combinations. 365 



examined after the apparatus had been in action for a certain number 

 of hours. 



The following are the conclusions which the author deduced from 

 a series of experiments thus conducted : 



1st. The force emanating from the active zinc centre diffuses itself 

 over every part of the upper hemisphere, from which there is a good 

 conducting passage for its circulation. 



2nd. The same amount of force is maintained by either hemisphere 

 indifferently ; but when both conducting hemispheres are in metallic 

 communication there is no increase of force. 



3rd. Although the force is not increased, it spreads itself equally 

 over the whole sphere. 



4th. When one hemisphere is connected with the zinc centre by 

 a short wire capable of affording circulation to the whole force, and 

 the other hemisphere is connected by a long wire, through the gal- 

 vanometer, with the same centre, the equal diffusion of the force over 

 the whole sphere is maintained. 



5th. There is no greater accumulation of precipitated copper about 

 the point with which the conducting wires are brought into contact, 

 and towards which the force diffused over the whole sphere must 

 converge, than at any other point; proving that the force must diverge 

 from the centre equally through the electrolyte, and can only have 

 drawn towards the conducting wires in the conducting sphere itself. 

 Other experiments showed that the force is but slightly increased by 

 a great increase of the generating surface. 



The author's attention was next directed to ascertaining the nature 

 of the law according to which the force emanates from the zinc centre 

 to the surrounding conducting sphere. With this view, a variety of 

 experiments were made with the zinc in different positions in the in- 

 terior of the sphere ; and from these it appeared that, whatever may 

 be its position, the whole force is the same. From these results it 

 is inferred, that the force emanating from the zinc ball diffuses itself 

 over the surrounding conducting sphere in obedience to the well- 

 known law of radiant forces being in the inverse duplicate ratio of 

 the distance. 



Experiments of the same kind were likewise made with the pre- 

 vious combination inverted, that is, with a small copper ball in the 

 interior of a large hollow sphere of zinc ; and from these the author 

 concludes that, in this case also, the law of radiation is maintained, 

 although the force is reduced to one half of that obtained from the 

 former combination. 



In order to ascertain the effect of cutting off the lateral radiation 

 from the zinc ball, it was placed in a glass tube, six inches long, 

 within half an inch of the lower aperture, over which a piece of mem- 

 brane was tied, and the tube plunged into the solution of copper con- 

 tained in a brass hemisphere, so as to rest upon the bottom. The 

 results obtained by this arrangement, as also those when the zinc ball 

 was raised in the tube to the surface of the solution, showed that the 

 action of the zinc ball had been propagated from the aperture of the 

 glass tube, as from a centre, diverging from this in the solution. 



