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the use of a membranous partition, and two different liquids, 

 to separate the respective metals ; but added, that the form 

 this philosopher adopted was imperfect, in consequence of 

 the difficulty of affixing the membranous portion staunchly 

 to the sides of the square glass box which contained the 

 two different fluids. 



The author, after referring to the sustaining battery of 

 Professor Daniel and to the modification of that appara- 

 tus adopted by Mr. MuUins, exhibited to the Academy a 

 battery which he had devised to remedy a defect affecting 

 all previous combinations, and in which each surface of the 

 hollow zinc cylinder had, as first recommended by Mr. 

 Wollaston, a surface of copper opposed to it. An account 

 was also given of several experiments which shewed the 

 advantage of his form in calorific and electro-magnetic ex- 

 periments. 



Mr. Clarke's improvement consists in attaching a ring of 

 zinc by zinc rivets to the top part of the outside of the hollow 

 cylinder of zinc used in the arrangement of Mr. MuUins, 

 and drawing a bladder over this cylinder, to which it is 

 secured by a cord to the ring ; and in replacing the earthen- 

 ware jar by a copper cylinder, which is furnished with a 

 mercury cup, as are also the zinc cyHnder and the central 

 copper. The central copper and the outer copper case are 

 connected by a wire dipping into the cups. A solution of 

 sulphate of copper is poured, as well into the outer case of 

 copper, as into the bladder surrounding the central copper, 

 and muriate of ammonia into the bladder enlosing the zinc. 



The author concluded by detaiHng some experiments, 

 tending to shew that, (contrary to the opinions of M. Mari- 

 anini and Mr. MuUins,) the maximum effect is obtained when 

 the surface of the zinc element is equal, or nearly so, to that 

 of the copper. 



Resolved, on the recommendation of the Council,— That 



Q 



