OF GALVANIC APPARATUS. 177 



SMEE'S VOLTAIC BATTERY. 



The great advantages of this battery consist in its power, as well as simplicity, 

 and the ease with which it is put in action, no obnoxious or unpleasant gases are 

 evolved from it, and the attachment being made by the binding screws, old plates may 

 be removed and new ones added with perfect ease, thus with one acid solution and no 

 porous diaphragm, continuous action for several hours is obtained. 



The solution consists of one part of concentrated sulphuric acid and seven parts of 

 water ; in preparing it put the water first into a glass vessel and add the sulphuric acid 

 slowly (to prevent much heating), a little only at a time; there must be no other 

 acid added to it, nor salts of any kind ; let the mixture become cold before putting it 

 into the battery. 



2068. Sttiee's Battery, single cell with platinized silver plate and two amalgamized zinc 



plates, in round earthenware or glass jar, with two binding screws, 1 pint, 7s.; 

 1 quart, 9s. 6d. ; 2 quart . . . . . 16 



2069. SMEE'S BATTEEY, a set of 6 in square porcelain cells, in mahogany tray with 



plates, and appendage for raising the plates from the acid when required, etc., 

 pint size, 3 ; a set of 6 ditto, ditto, quart size (fig. 2069), p. 176 3 10 



The general arrangement of this set, and the facility with which the leading facts con- 

 uected with galvanism, as the decomposition of water, deflagrating metals, etc., etc., may be 

 shown by it, adapts it admirably for public instruction. 



2070. Educational Set of Apparatus, viz., electro-magnetic coil machine, Smee's 



battery, galvanometer, Ritchie's experiment, Oersted's ditto, electro-magnet 

 on mahogany stand, Barlow's wheel and permanent magnet, in coloured deal 

 case, with lock and key , . . . . 550 



GROVE'S BATTERY. 



The solutions required for this battery are concentrated nitric acid unmixed, in the 

 platinum or porous cell, and diluted sulphuric acid in the zinc or glass cell, the propor- 

 tions being 7 of water to 1 of sulphuric acid. 



2072. Grove's Platinum Battery (single), in flat glass cell, with porous lining, pair of 



zinc plates, 2 brass connectors, size of platinum, 4 inch, by 2 inch. 12 6 



2073. GEOVE'S BATTEEY, as above, 5 cells in mahogany frame, the platinum plates 6 



by 3 inch., the proper size (for safety) to use with Ruhmkorff's coil 4 10 



2074. GEOVE'S BATTEEY, of 8 cells, the platinum plates 6 by 3J inch., in handsome 



polished mahogany frame with brass fittings complete . 6 10 



