304 SEC. 10. ELECTRICITY. 



the square aperture in the lid, and by a simple manipulation the cork is 

 pushed from the open end af the glass tube. 



1259a. Muirhead's new Manganese Battery. 



Warden, Muirhead, and Clark. 



The positive plate is of zinc of a hollow cylindrical form placed in a perforated 

 vitreous chamber. The negative plate is of platinized carbon, surrounded with 

 lumps of platinized carbon and di-oxide of manganese. The exciting liquid 

 is a solution of muriate of ammonia. Its electro-motive force is 1 6 volts, 

 internal resistance, 2 ohms. Electro-motive force of a Daniell cell, 1 1 volts. 



1260. Gas Voltaic Battery devised by W. R. Grove, Esq,, 

 M.A., F.R.S., Professor of Experimental Philosophy in the Lon- 

 don Institution (now The Hon. Sir W. R. Grove), and described 

 by him in a communication read before the Royal Society, May 

 llth, 1843. Experiments with this battery are described in a 

 postscript, dated July 7th (Phil. Trans., 1843, p. 91). 



London Institution, Finsbury Circus, E.G. 



It consists of a series of Woulfe's bottles, into the necks of which glass 

 tubes closed at one end are fitted by grinding ; each tube contains a slip of 

 platinum foil, coated with finely divided platinum, the slip being connected 

 with a wire sealed into the end of the tube, and terminating outside in a 

 little cup ; the cups being filled with mercury, the tubes may be connected by 

 wires dipping into the mercury. When the Woulfe's bottle and its tubes are 

 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 ; the current being gene- 

 rated, in fact, by the formation of water. 



1260a. The Original Nitric Acid Battery. 



The Hon. Sir W.R. Grove, F.R.S. 



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 fill the alternate upright glass tubes. Strips of 

 platinum passing down the tubes serve for making metallic connexion 

 with the gases. 



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

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

 m the London Institution (now The Hon. 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 



