[iRETOX] 



SELECTED RADIATION'S 



135 



Some experiments have been made by the writer to test out 

 experimentally the ideas set forth above. In particular an attempt 

 was made to see whether it was possible for mercury atoms to em't 

 radiation of the wave lengths X- 5460.97 A.U. and X = 4046.78 Â.U. 



I 5 s 



ORIG/N OF MERCURY RESON/iNŒ SPECTRA . 

 Fig 3. 



when they had previously been made to absorb successively light of 

 the wave lengths X = 2536.72 Â.U. and X = 4358.66 Â.U. Experi- 

 mental results were obtained which lend support to the idea. Some 

 experiments were also made in which it was found that mercury atoms 

 which had absorbed radiation of the wave length X = 2536.72 A.U. 

 were in the condition to absorb and subsequently re-emit the wave 

 length X = 4358.66 Â.U. while ordinary unstimulated atoms of mercury 

 were not. 



An account of the investigation follows. 



II. Apparatus and Experiments. 



A specially constructed mercury arc lamp, as shown in Fig. 4 

 was used. It consisted of a pyrex tube of about 4.5 cms. bore, closed 

 at the ends by plugs cemented into the tube. Supported inside this 

 were two small tubes, one of glass, the other of quartz of about 8 mm. 

 bore and having walls of equal thickness. These tubes were per- 

 manently closed at the left hand end. At the right hand their open 

 ends passed through and projected equal distances beyond the end 

 of the lamp. A quartz plate was cemented on to close the open ends 

 of these inner tubes. These were placed as symmetrically as possible 



