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PROCEEDINGS OF THE AMERICAN ACADEMY. 



were connected to the Plante machine, and the latter was excited, 

 the entire tube fluoresced brillianily. This fluorescence was especially 

 brisht in the connecting tube between the straijjht wire tube and the 

 Crookes tube, and a beam of light passed across the Crookes tube and 

 formed a fluorescent spot on its bulb. 



Figures 1 to 9. 



Photographic plates were exposed opposite to the thin bulb on the 

 straight wire tube. These plates were carefully insulated from the ground, 

 and were covered in one case with a sheet of hard rubber an eighth of an 



