f6 An Account of seme Experiments . 



within its own governing principles a power of periodic 



and revolutionary renovation. 



I am, sir, your most obedient humble servant, 



John Carr. 



trincess Street, Manchester, 

 July 5, 1809. 



IV. An AccoJint of some Experimenis, performed with a 

 View to ascertain the most advantageous Method of con- 

 structing a Voltaic Apparatus, for tlie Purposes of Chemi- 

 ealResearch. jBj/JohnGeokgkChilduen, Esq., F.R.S.* 



JL HE late interesting discoveries by Mr. Davy having shown 

 the high importance of the VoUaic battery as an instrument 

 of chemical analysis, it became a desirable object to ascer- 

 tain that mode of constructing it, by which the greatest 

 effect may be produced, with the least waste of power and 

 expense. 



For this purpose, I made a battery, on the new method, 

 with plates of copper and zinc, connected together by leaden 

 straps, soldered on the top of each pair of plates ; which are 

 twentv in number, and each plale four feet high, by two 

 feet wide : the sum of all the surfaces being 921 60 square 

 inches, exclusive of the single plate at each end of the bat- 

 tery. The trough is made of wood, with wooden partitions 

 well covered with cement, to render them perfectly tight, so 

 that no water can flow from one cell to another. The bat- 

 tery was charged with a mixture of three parts fuming ni- 

 trous, and one part sulphuric acid, diluted with thirty parts 

 of water, and the quantity used was 120 gallons. 



In the presence, and with the kind assistance of Messrs. 

 Davy, Allen, and Pepys, the following experiments were 

 made. 



Experiment 1. Eighteen inches of platina wire, of -j'jjth 

 of an inch diameter, were completely fused in about twenty 

 seconds. 



* From Philosophical Tran^artjone for 18C9, Parr I. 



2 F.xp. 



