TRANSACTIONS OF SECTION A. 579 



In hydrogen the luminosity is very much less than in any of the other gases 

 ■when the current has been shut off as long as one-thousandth of a second. 



In oxygen the floating cloud is very brilliant. In coal gas it is barely visible, 

 and of a decidedly reddish hue. In this case the interior of the hood is lined with 

 a deposit of carbon. Query, Is this red light due to carbon incandescent at the 

 moment of dissociation from the hydrogen ? 



The spectrum of the blue arc is the ordinary iron-arc spectrum. 



The spectrum of the yellow cloud which persists is also a linear spectrum of 

 iron ; but the distribution of intensities among the lines is very different indeed 

 from that of the ordinary u'on arc. The investigation of the difference between 

 these two spectra when separated in this way is a comparatively easy matter. 

 This investigation is already under way. 



11. On some JVeto Forms of Gas Batteries and a Neio Carbon-consuming 

 Battery} By Willard E. Case. 



In 1839 Grove announced his invention of the gas battery; he considered it the 

 most simple arrangement to produce electricity, but not a practical way to generate 

 electrical energy. He used platinum sponge or platinum black as the absorbent 

 to fiicilitate the combination of the gases. The following experimental determina- 

 tions by the author show, as far as they extend, that platinum or its compounds 

 are not necessary to produce the combination of the gases in the production of 

 electrical energy, so doing away with one of the most expensive drawbacks to the 

 gas battery. The experiments also prove that carbon is oxidised to CO.^ at 

 normal temperature without the application of heat, with the production of 

 electrical energy. 



The Chlorine- Carbon Cell, 



A porous carbon tube-electrode, into which chlorine gas was passed, opposed 

 to a carbon rod, which had been heated red hot, were placed in hydrochloric acid, 

 of specific gravity 1-10. An E.M.F. of from 0-50 to 0'64 vole was obtained, 

 depending on the condition of the carbons. 



The carbon electrodes, after being heated, were placed in distilled water. With 

 no chlorine gas passing through they had no difference of potential. When gas 

 was passed into the carbon tube, at slightly above atmospheric pressure, the 

 E.M.F. gradually increased to 0'44 of a volt at the end of twenty-six hours. On 

 short circuit, 0-04 of an ampere was obtained, but it dropped rapidly to 0-02. The 

 internal resistance was very high. The solution was analysed, and found to con- 

 tain hydrochloric acid and carbon dioxide. The same experiment was repeated in 

 a dark case, to see if the action took place in the absence of light. The chlorine 

 gas was made in the dark and passed though the electrode. The electromotive 

 force gradually increased, as in the first case, showing that the action took place 

 in the dark. 



A carbon electrode, through which chlorine was passed, and a negative plati- 

 num electrode opposed to it, in dilute hydrochloric acid, gave 0'40 of a volt, but 

 the electromotive force did not hold up through the voltmeter circuit. Both 

 electrodes were covered with gas after short-circuiting, and the E.M.F. dropped 

 to 0-24 of a volt. On shaking the voltage jumped to 0-40. 



A negative carbon electrode was substituted for the negative platinum. It had 

 been heated red hot and was very porous, the surface soft and rough. The 

 E.M.F. reached 0-58 of a volt, and gave on short circuit 1-24 ampere, but 

 dropped slowly to 0-30. The negative carbon electrode was oxidised. 



A platinum electrode in a paper envelope was opposed to powdered carbon in 

 the bottom of a glass jar in hydrochloric acid, chlorine being passed into the solu- 



' Published m fa;#e;tsy in the Electrician, Sept. 17, 1897, and in the Electrical 

 Engineer (New York), Sept, 2, 1897. 



P p2 



