Chemistry and Physics. 417 



2. On an improved form of Grove's Gas Battery. — Mo:nt> 

 and Langer have experimented with the gas battery of Grove 

 with a view of utilizing it commercially. In its improved form 

 it consists of a fiat porous diaphragm of non-conducting material 

 having transverse metallic strips let in to its surface at intervals, 

 and covered on both sides with thin platinum foil having 1,500 or 

 more perforations per square centimeter, this foil being covered 

 with platinum black. Several such diaphragms are placed together, 

 with non-conducting frames intervening so as to form chambers, 

 and immersed in dilute sulphuric acid. A current of air is passed 

 through one set of these chambers and a current of hydrogen 

 through the other set alternate with these, so that one side of 

 each diaphragm is exposed to one gas only. The best platinum 

 black for this purpose was obtained by reducing a boiling alka- 

 line solution of platinic chloride with sodium formate ; an elec- 

 tromotive force of 0*97 volt being thus obtained. In practice it 

 was found preferable to work the battery at 0'73 volt; in which 

 case a battery having 700 sq. cm. of active surface, covered with 

 0*35 gram of platiuum foil and one gram of platinum black gives 

 a current of 2 to 2-5 amperes. It was observed that no less than 

 half the energy of combustion of the hydrogen is obtained as 

 electrical energy. No material advantage results, from the use of 

 pure oxygen and hydrogen over that of air and water gas, the 

 latter obtained by passing steam over red hot coke. The tem- 

 perature should be maintained constant at 40° by regulating the 

 supply of air. — Proc. Roy. Soc, xlvi, 296 ; J. Chem. Soc, lviii, 

 841, Aug., 1890. G. F. b. 



3. On the formation of Hydrogen Peroxide from Ether. — 

 Dlhststan and Dymond have studied the conditions under which 

 hydrogen peroxide is formed from ether. They find that con- 

 trary to the received opinion, no hydrogen peroxide is formed 

 when properly purified ether is exposed to light under ordi- 

 nary atmospheric conditions, either in contact with air or water ; 

 the results recorded by former observers having been due appar- 

 ently to the use of impure ether When prepared by the action 

 of sodium ethoxide in excess on ethyl iodide, and exposed to full 

 daylight for five months and to the electric light for two months 

 for three hours nightly, the ether showed no reaction with potas- 

 sium iodide, hydriodic acid or chromic acid. The ether produced 

 by the action of sulphuric acid on alcohol and purified with sul- 

 phuric acid and potash, however, reacted faintly with potassium 

 iodide and decidedly with hydriodic acid but not with chromic 

 acicl ; while the ether prepared from methylated spirit and exposed 

 to light contained a considerable amount of hydrogen peroxide. 

 The authors have not been able to ascertain the nature of this im- 

 purity in the ether, owing to its minute quantity. The impure 

 ether examined by them which w 7 as richest in hydrogen peroxide 

 contained only - 04 per cent of this substance, although it had 

 been for many years exposed to the light. The authors find, 

 however, that ether absorbs the entire molecule of ozone prob- 

 ably, as turpentine does, and on shaking the ether afterward with 



