312 



MM. Oumoff and Samoiloff on Electric 



should therefore obtain this by constructing curvilinear rajs 

 emerging from certain points of the tube in the direction of 

 Fig. 4. Fig. 5. 





the opening. Thus we see generally that transporting the 

 object from one side of the screen to the other results in the 

 interversion of the phenomenon. 



We may mention that a metallic strip with parallel mar- 

 gins, curved into a circular arc and fixed by its summit on 

 the screen (fig. 6), gives a black shadow (fig. 7) enlarged at 

 its two ends and surrounded by a reddish field. 

 Fisr. 6, Fig-. 7. 







■ :l!i 



(6) Fig. 8 shows the image of a lead band, curved and 

 fixed vertically on the screen by one of its margins. Fig. 9 



Fig. 8. 



shows the change which the image undergoes when a glass 

 plate is placed beneath the ebonite screen. 



(7) Lead strips of equal length but different widths were 

 bent into circular cylinders of the same diameter (about 2 cm.). 

 On placing one of these cylinders vertically on the ebonite 

 screen its base is represented by a red circle ; in the interior 

 there is a thin black band (neutral) which surrounds a yellow 

 spot. On placing a glass plate beneath the ebonite the central 

 yellow spot diminishes markedly and the neutral bands in the 

 interior, as well as at the exterior, increase in width. The 



