MR. DANIELL ON VOLTAIC COMBINATIONS. 47 



Standard Acid. Dilute Acid. 



The zinc ball placed near the bottom, connexion with 



top insulated hemisphere 52 .... 42 



Connected with bottom 59 .... 50 



The zinc ball placed near the top, connexion with bottom 



insulated hemisphere 51. ...41 



Connected with top 59 .... 50 



Both hemispheres connected 59 ... . 



In these experiments, that hemisphere alone with which the connexion had been 

 made could have influenced the results as a conducting surface. 



A question now occurred to me of extreme interest : admitting that the force ge- 

 nerated in the preceding combinations where it was limited in its diffusion by the 

 concave surfaces of spherical forms, follows in its action the law of radiant forces, 

 we know that it is not a simple radiant force like that of gravity, but a molecular 

 force propagated from particle to particle, and possibly modified by other forces with 

 which the same particles may be endowed. The law of radiation, if established, may, 

 therefore, be the result of the concurrence of more than one force, limited by the sphe- 

 rical combinations with which we have been dealing. The physical law, in ordinary 

 cases, supposes both the sphere and the point within to consist of similar attractive 

 matter ; and were the force which we are now investigating of the same nature, it 

 would make no difference whether the sphere consisted of merely conducting metal 

 and a small interior generating ball, or whether the sphere consisted of generating 

 metal and the ball were an inactive conductor, — inactive I mean with regard to the 

 electrolyte. What experimental results, therefore, would the latter combination 

 afford ? 



I caused two hemispheres of zinc to be made of exactly the same form and dimen- 

 sions as those of copper, and fitted together in the same way; the interior surfaces of 

 these were thoroughly amalgamated with mercury. When wedged together by their 

 flanges and ring of leather, metallic contact was preserved between the two by a 

 small interior ring of amalgamated zinc. The sphere was charged with dilute acid, 

 and the interior membranous bag with the acid solution of copper. A copper ball 

 of one inch diameter fixed to the end of a varnished wire was then immersed in the 

 latter, and a circuit formed by contact with different parts of the zinc sphere with 

 the intervention of the calorific galvanometer. 



The indications of the instrument were as follow : — 



Ball at the top 36 



Ball at the centre 36 



Ball at the bottom 36 



Again at the top 35 



