44 



flanges, and rendered water-tight by an intervening collar of leather. 



In the centre of the hollow sphere thus formed, a ball of amalgamated 

 zinc was suspended by a well- varnished copper wire, connected with 

 one of the cups of a galvanometer, and was contained in a mem- 

 branous bag holding the acid solution ; the whole being introduced 

 through a short tube in the top of the upper hemisphere, and the 

 remaining space being filled with a saturated solution of sulphate of 

 copper. The galvanic circuit was completed by wires establishing 

 connexions between either hemisphere and the other cup of the galva- 

 nometer. For measuring the forces developed, sometimes the ordi- 

 nary magnetic, but in the greater number of instances the calorific 

 galvanometer of De la Rive was employed ; the indications given by 

 these instruments were noted, on the completion of the circuit, in 

 various ways ; and the deposition of copper in the hemispheres was 

 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 Avere likewise made with the pre- 



