MR. DANIELL ON VOLTAIC COMBINATIONS. 



53 



This point is doubtless dependent upon the angle at which the force, which radiates 

 (as it were) from the ball, meets the edge of the plate. 



Wishing now to draw the preceding experiments into closer comparison with similar 

 ones which had hitherto, generally, been made in a different form, I had a square glass 

 cell constructed, measuring 3^ inches and four deep. This was cut in two in the 

 middle, and the edges having been ground admitted of being clamped together, with 

 the interposition of a piece of bladder. When thus put together it formed a cell di- 

 vided into two by a diaphragm of membrane in the liquid, on either side of which 

 different generating and conducting plates might be immersed. The forms which I 

 selected were copper and zinc plates 3J inches square, and copper and zinc balls of 

 one inch diameter : the results obtained by different combinations of these, at dif- 

 ferent distances apart, measured by the calorific galvanometer, are contained in the 

 following Table. The electrolyte which was employed was, in one series, the standard 

 acid on both sides of the diaphragm, and in the other the same acid in contact with 

 the zinc, and the solution of copper with the copper. In the near distance the sur- 

 faces were about half an inch apart ; in the farther three inches ; and the balls were 

 always placed opposite to the centre of the associated plate. 



The precipitated copper in all these cases had been pretty evenly diffused over the 

 near surface of the plates, and was to be traced to all parts of the opposite surface, 

 but more upon the edges than towards the centres. 



Upon this Table we may remark : — 



1st. That the energy of the force was about sextupled by the absorption of the 

 hydrogen upon the conducting surface, except in the case of the equal plates, when 

 it was more than quadrupled. 



2nd. That the effect of distance was much more decided in the instances where 

 the amount of the circulating force was greater, than in the contrary cases. 



3rd. That the amount of force put into circulation from a large surface of zinc 

 towards a central ball of copper was, as in former instances of similar combinations, 

 about one half of that from the reverse arrangement. 



4th. That a ball of zinc exposing a surface of 3*14 square inches placed over the 

 centre of a plate of copper exposing on its two sides a surface of twenty-eight square 

 inches, sustained an action of nearly the same amount as a plate of zinc of the same 

 dimensions as the copper, placed at the same distances. 



This result, as well as the small effect produced in preceding experiments by sub- 

 stituting two equal balls, or a rod, for one ball of zinc, may, upon the supposition of 



