CHAPTER IV. 



PHOSPHORESCENCE OP GASES, AND ELECTEIC 

 PHOSPHORESCENCE. 



THE phosphorescence of gases is quite a new dis- 

 covery, dating from the year 1859. It is extremely 

 probable that many gases are phosphorescent after 

 insolation, when large quantities of them are sub- 

 mitted to the action of the sun's rays. We shall 

 see in the following chapter that the air probably 

 is so, and also that meteoric stones leave phospho- 

 rescent streaks in the atmosphere. 



We have already noticed, that substances which 

 are not phosphorescent after insolation may be- 

 come so after they have undergone the influence 

 of an electric discharge. In February, 1 859, M. 

 Edmond Becquerel communicated to the A cademy 

 of Sciences at Paris a discovery made by M. Ruhm- 

 korff on rarefied air, and worked out afterwards 

 by the former. 



M. Euhmkorff remarked that certain rarefied 

 gases, shut up in glass tubes, remained phospho- 

 rescent for some seconds after an electric dis- 



