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 LXI. Intelligence and Miscellaneous Articles. 



ON THE THOSPHORESCENCE OP GASES BY THE ACTION OF ELEC- 

 TRICITY. BY E. BECQUEREL. 

 IN the Memoirs presented by me to the Academy on the 16th of 

 November, 1857, and •24th of May, 1858, relative to the lumi- 

 nous effects presented by bodies after having received the influence 

 of light, I made use of tubes containing rarefied air, and in which 

 were placed phosphorescent substances which became luminous 

 after the passage of electrical discharges. Some time afterwards, 

 M. Ruhmkorflf, who arranged these apparatus in accordance with 

 my directions, called my attention to the fact that in certain tubes 

 containing only rarefied gases, which had been sent to him by M. 

 Geissler, there were to be seen, after the passage of discharges, 

 luminous traces persisting only for a few seconds, and analogous to 

 those diffused by the phosphorescent substances employed in my 

 investigations. 



I have since studied the passage of electrical discharges through 

 rarefied gases and vapours, which gives rise, as is well known, to 

 effects of colour depending on their nature, with the view of ascer- 

 taining what are the gases which present the effect of persistence of 

 light, and whether the phaenomenon be analogous to the phseno- 

 menon of phosphorescence observed with solid bodies. In most 

 tubes containing such gases as hydrogen, sulphuretted hydrogen, 

 protoxide of nitrogen and chlorine, we observe faint gleams persist- 

 ing after the passage of induction electricity, or even of a simple 

 discharge of an electric battery, but the action appears to be limited 

 to the internal surface of the glass tube. It is not due to phospho- 

 rescence of the glass ; for tubes exposed to the action of a brilliant 

 light, and then carried again into the dark, give rise to no action of 

 this kind, and the phosphoroscope must be employed to observe the 

 effects of persistence upon the glass, the duration of which is shorter 

 than that which follows the action of electricity; the effect presented 

 by tubes containing these gases would therefore appear to be 

 the result of an electrization of the glass, or of the adherent gaseous 

 stratum. 



With oxygen a different effect is observed ; when the discharges 

 of a strongly excited induction apparatus are passed through a tube 

 containing this gas in a rarefied state, and the passage of the elec- 

 tricity is suddenly stopped, the tube appears to be illuminated 

 with a yellow tint, which persists for several seconds after the inter- 

 ruption, and decreases more or less rapidly according to conditions 

 which I have not yet been able to ascertain. In order that the 

 effect may be very manifest, the electricity transmitted into the gas 

 must have a certain tension ; it is therefore preferable to inter- 

 pose a condenser in the circuit, and to excite sparks at a distance 

 in the air between one of the conductors of the induction apparatus, 

 and one of the platinum-wires penetrating into the tube. A simple 

 discharge of an electrical battery of several jars produces the same 

 effect. In order to observe the persistent luminous action, the oper- 

 ations must be carried on in the dark ; care must also be taken to 



