On Radiant Matter. 17 



of rest the glass partly recovers its power of phosphor- 

 escing, but it is never so good as it was at first. 



FIG. 10. 



Here, therefore, is another important property of Radiant 

 Matter. It is projected with great velocity from the nega- 

 tive pole, and not only strikes the glass in such a way as to 

 cause it to vibrate and become temporarily luminous while 

 the discharge is going on, but the molecules hammer away 

 with sufficient energy to produce a permanent impression 

 upon the glass. 



Radiant Matter exerts strong mechanical action where it 



strikes. 



We have seen, from the sharpness of the molecular sha- 

 dows, that Radiant Matter is arrested by solid matter placed 

 in its path. If this solid body is easily moved the impact of 

 the molecules will reveal itself in strong mechanical action. 

 Mr. Gimingham has constructed for me an ingenious piece 

 of apparatus which when placed in the electric lantern 

 will render this mechanical action visible to all present. It 

 consists of a highly-exhausted glass tube (Fig. n), having 



FIG, IT. 



a little glass railway running along it from one end to the 

 other. The axle of a small wheel revolves on the rails, the 



c 



