592 Royal Irish Academy. 



the same size as the former platinum, affording an oeconomical me- 

 thod of arranging a Wollaston's battery, the zincs being bent round 

 the coppers, in place of the coppers round the zincs. 



" Experiments with Grove's Battery. — The acid solutions were those 

 recommended by Mr. Grove, i. e. pure nitric acid, in contact with 

 the platina ; sulphuric acid + 4'5 water by measure, in contact with 

 the zinc. The surfaces of zincs immersed were 3 by 2*5 inches; 

 those of the platina, bent round the porous vessel holding the zincs, 

 were 6 by 2*5 inches. The glasses containing the acid, &c, were 

 32 inches long, T5 broad, 3*5 deep. The length of the porous 

 vessel of pipeclay was 2*5 inches, the breadth 03, the depth 3*5. 

 The number of alternations was five. 



Cubic inches. 

 Time, 2 minutes 8'0 



8-0 

 30 

 1-0 

 none 



The battery being at rest for 10 minutes 



25 : . . . . 



... ... 1 hour . . 



... ... 19 hours . 



" The porous vessel was found filled with sulphate of zinc, which 

 stopped the action of the battery. 



" Second Experiment. — The zinc plates being of the same size as 

 the former platina, and the platina of the same size as the former 

 zincs; the zincs bent round the platina; all other things being as before. 



Cubic inches. 



Time, 2 minutes 8 - 



After 10 minutes 8* 



... 25 8* 



" Third Experiment. — Another battery, the diameter of the cells of 

 which was 2\ inches, gave a diminution of only one-half of the quan- 

 tity of gas after the lapse of forty -eight hours, showing the advantage 

 of having a large supply of sulphuric acid*. 



" Experiments with Smee's Battery of Platinized Silver. — The acid 

 solution was of the same strength as before, and the sizes of the 

 zincs and platinized silver the same as of the zincs and platina for- 

 merly employed. The zincs were bent round the platinaf. 



Cubic inches. 



Time, 2 minutes 3* 



After 5 minutes 2*6 



" Second Experiment. — The zincs being raised out of the acid, 

 cut in two, and re-immersed. 



* "The porous vessels were of pipeclay- The same experiments repeat- 

 ed with unglazed porcelain gave 10 cubic inches in two minutes ; with very 

 porous pipeclay, they gave as much as 15 cubic inches in two minutes, 

 showing the importance of attending to the nature of the porous vessel 

 employed." 



f " The most advantageous method of arranging a Smee's battery is, 

 packing the zincs and platinized silvers in the manner recommended by Dr. 

 Faraday in his tenth series, (also by Mr. Young, Phil. Mag., S. 3. vol. x. p. 

 241) placing the package en supports so as to allow the sulphate of zinc to 

 fall to the bottom of the vessel, while the fresh acid rises to the surface." 



