262 SEC. 10. ELECTRICITY. 



1257a. Forty Cells of a Bod Chloride of Silver Battery, 



being part of a battery of 8,040 cells. 



Warren De la Rue, F.R.S., and Hugo W. Midler, F.R.S. 



The elements consist of a silvered flattened wire and a zinc (non-amalga- 

 mated) rod. The electrolytes are a solution of chloride of ammonium, 23 

 grammes to a litre of water, and fused chloride^ of silver cast on to the silver 

 wire. 



When the terminals are not connected the battery is quite inactive ; one 

 such battery has been in action since November 1874. In order to prevent 

 contact between the chloride of silver and the zinc rod, the rod of chloride of 

 silver is encased in a tube of vegetable parchment open at both ends. The 

 cell is a glass tube closed with a paraffin stopper. 



Such a battery will evolve three cubic centimetres of mixed gases, if con- 

 nected up with a voltameter containing one volume of sulphuric acid, and eight 

 volumes of water. 



This battery is particularly well suited to experiments with a large number 

 of elements, on account of its constancy. 



1258. Portable Medical Battery, with modified form of 

 Be La Rue's chloride of silver and zinc elements. 



Tisley and Spiller. 



1259. New Galvanic Battery for Domestic Purposes. 



Aurel de Ratti, Bradford Grammar School. 



This Zinc-Carbon Battery is" charged with a saturated solution of sulphate 

 of magnesia or Epsom salts, a very cheap material. The flask above the cell 

 is filled with crystals of this salt, on which a saturated solution of the same is 

 poured until the flask is quite full. The cork with the glass tube is then 

 forced down till the solution rises and fills the tube. A small cork is loosely 

 fixed in the open end of the glass tube. No air must be allowed to remain in 

 the tube or flask. The latter is now inverted, and the tube introduced through 

 the round hole in the lid. The flask will be held in position by the projecting 

 cork fitting into the round hole. The end of the glass tube will thus be im- 

 mersed in the solution in the jar. The carbon- plate is finally pushed through 

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

 pushed from the open end of the glass tube. 



1259a. Muirhead's new Manganese Battery. 



Warden, Muirhead, and Clark. 



1260. Gas Voltaic Battery devised by W. E. Grove, Esq<, 

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

 don Institution (now Justice 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.C. 



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 which terminates 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 



