I. BATTERIES. 263 



filled with dilute sulphuric acid, and one of the tubes is then charged with 

 hydrogen and the other with oxygen, in quantities such as will allow the 

 platinum to touch the acid, and the ends of a wire are dipped into the cups 

 at the tops of the tubes, an electric current is produced. At the same time 

 the gases in the tubes gradually diminish in volume, the volume of hydrogen 

 which disappears being double that of the oxygen, and the current being 

 generated, in fact, by the formation of water. 



1261. Grove's Gas Battery, made by Spencer and Son, 

 Dublin. Prof. W. F. Barrett. 



The current in this battery is produced by the gradual union of the gases 

 oxygen and hydrogen, which alternately fill the upright glass tubes. Strips 

 of platinum passing down the tubes serve to make metallic connexion 

 throughout the circuit. 



1262. A Constant Gas Voltaic Battery devised by W. R. 

 Grove, Esq., M.A., F.R.S., Professor of Experimental Philosophy 

 in the London Institution (now Justice Sir W. R. Grove), and 

 described by him in a communication to the Royal Society, dated 

 May 30th, 1845. London Institution , Finsbury Circus, E.C. 



To charge the apparatus, the stopper is removed from the end of the tube, 

 and the glasses are filled to the top of the narrow platinum plates with 

 acidulated water ; acid is also poured into the end vessel, so as to cover the 

 lump of zinc. The hydrogen which is evolved by the action of the zinc 

 on the acid gradually expels the air from the main channel, and, when this is 

 judged to be the case, the stopper is inserted; the hydrogen now will rapidly 

 descend in all the tubes until the zinc is laid bare, and then remain stationary. 

 A gas battery is now obtained, the terminal wires of which Avill give the usual 

 voltaic effects, the atmospheric air supplying an inexhaustible source of 

 oxygen, and the hydrogen being renewed as required by the liquid rising to 

 touch the zinc ; by supplying a fresh piece of zinc when necessary it thus 

 becomes a self-charging battery, which will give a continuous current ; no new 

 plates are ever needed ; the electrolyte is never saturated, and requires no 

 renewal except the trifling loss from evaporation, which indeed is lessened, if 

 the battery be in action, by the newly composed water. 



1263. Element of M. Becquerel's Sulphate of Copper 

 Battery. Conservatoire des Arts et Metiers, Paris. 



1264. Twelve Elements of Galvanic Batteries on different 

 systems, by Ruhmkorff. Conservatoire des Arts et Metiers, Paris. 



1265. FouiUet's Thermo-Electric Battery. 



Conservatoire des Arts et Metiers, Paris. 



1266. Smee's Battery. Six cells, with arrangement for 

 raising the plates out of the cells. James How $ Co. 



1266a. Set of Six Cell Smee's Batteries. 



E. Cetti and Co. 



1267. Winter's Machine, with 18-inch ebxmite plate and 

 condenser attached, for the Accumulation of electricity. 



Elliott Brothers. 



