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XXX. On a new and practical Voltaic Battery of the highest 

 powers, in which Potassium forms the positive element. By 

 John Goodman, Esq.* 



|30TASSIUM is well known in science as one of the most 

 -*- powerful chemical substances, possessing chemical affini- 

 ties and powers of the highest order. This substance appears 

 to have been long known also in an electrical point of view, 

 for we find it arranged by Sir H. Davy and others at the head 

 of a list of positive and negative metals, in which it forms the 

 principal oxidizable metal, being, with its amalgams, electro- 

 positive to all other metals arranged in electrical relations 

 with it. 



It was with this knowledge of the high powers of potassium, 

 that the author, whilst pursuing his researches into the analogy 

 of light, heat, electricity, &c., devised several experiments with 

 the intention of constructing a voltaic arrangement, in which 

 this metal should form one element. At first, the potassium, 

 amalgamated, was suspended by a copper wire in mineral 

 naphtha, floating upon dilute sulphuric acid. In the acid 

 liquid a plate of platinum was arranged, in connexion with 

 one extremity of the galvanometer, to the opposite extremity 

 of which the potassium wire was attached. On lowering the 

 potassium down to the surface of the acidulated water, a cur- 

 rent of 60° or 70° was observed, and a strong action ensued, 

 which after a few moments generally dislodged the metal from 

 its connexions, and put an end to the experiment. 



After many fruitless attempts permanently to fasten the 

 metal upon its wire of communication, it was remembered that 

 in one instance a very efficient voltaic pair had been formed, 

 in which a simple copper wire of a spiral form merely sur- 

 rounded the wet bladder in which the zinc element was im- 

 mersed in dilute acid, being only in contact with, and acting 

 through, the substance of the membrane, although unimmersed 

 in any fluid. Advantage was taken of this knowledge, and it 

 was contemplated that potassium might, as possessing such 

 extraordinary affinities, also act upon water through an inter- 

 vening membrane. Thus might its excessive action be mode- 

 rated, and itself rendered probably quiet and manageable. 



On the 5th of May last the following plan was ultimately 

 adopted after much consideration, and proved successful be- 

 yond my most sanguine expectations. A wine-glass was filled 

 with dilute sulphuric acid, and in this was immersed a plate 

 of platinum just below the surface of the liquid. At the ex- 



* From the Manchester Literary and Philosophical Society's Memoirs, 

 vol. viii. Communicated by the Author. 



