478 SCIENTIFIJ RECORD FOR 1884. 



cell, its electro-motive force being 0.82 volt between' 5° and 40°. {J, 

 Fhys., October, 1884, II, in, 444, 448.) 



Lalande and Chaperon suggest cux^ric oxide as the depolarizing agent 

 in the battery. The oxide is placed on the copper plate, which is 

 cov^ered with a solution of caustic potash, and a plate of zinc is suspended 

 in it. The electro-motive force is 0.98 volt and the cell is remarkabl^'^ 

 constant. (Nature, January, 1884, xxix, 227.) 



Tommasi and Eadiquet'have constructed a battery with two carbon 

 electrodes. The positive plate is placed at the bottom of a porcelain 

 jar and covered with lead peroxide, the negative plate is covered on 

 its surface with platinized coke, the two being separated by a sheet of 

 parchment paper. A solution of common salt is used as the electro- 

 lyte, which must not com])letely cover the upper plate. The electro- 

 motive force on closed circuit is 0.6 volt. {G. B., July, 1884, xcix, 120.) 



Pabst has invented an iron cell, the electrodes of which are carbon 

 and wrought-irou in a solution of ferric chloride, and which is claimed 

 to be non-polarizable and self-regenerating. The oxj^geu of the air is 

 absorbed in the working of the battery, and ferric oxide is deposited at 

 the bottom of the cell. Its electro-motive force is about 0.78 volt. [Na- 

 ture, January, 1885,- xxxi, 203.) 



Bartoli has designed a battery in which the material consumed is 

 carbon, which is in the form of a compacted mixture of Ceylon grai)hite 

 and retort coke. This constitutes one of the electrodes, while the other 

 one is platinum. The exciting liquid is sodium hypochlorite, and the 

 electro-motive force is only about 0.2 volt. {Nature, January, 1885, 

 XXXI, 203.) 



Jablochkoff has produced a battery of considerable scientific interest. 

 A small rod of sodium, weighing about 8 grams, is squeezed into con- 

 tact with an amalgamated copper wire and flattened. It is then wrapped 

 in tissue paper and fastened by wooden pegs to a jjlate of very i^orous 

 carbon. The sodium absorbs the moisture of the air and no solution is 

 required. Its electro-motive force is 2.5 volts, but its resistance is 25 

 ohms. (Nature, January, 1885, xxxi, 203.) 



Skrivanow's battery consists of zinc and of silver chloride enclosed 

 in parchment paper and immersed in a solution composed of 75 parts 

 caustic potash in 100 of water. The enclosing vessel is a hard rub- 

 ber cup which is hermetically sealed, and the whole weighs 100 grams. 

 The electro-motive force is from 1.45 to 1.50, and the cell will give a 

 current of 1 anipere for about an hour. Then the solution must be re- 

 newed, and after two or three renewals of this the silver chloride must 

 be replaced. (C. jB., January, 1884, xcviii, 224.) 



Gore has constructed a new and convenient form of thermo-electric 

 apparatus for measuring small electro- motive forces by the method of 

 opposition. It consists of about 300 horizontal, slender, parallel wires 

 of iron and German silver, the former covered with cotton. These 

 wires are about 8 inches long, fixed side by side in close mutual con- 



