]\lr. A. A. Campbell Swinton. 

 TIB. 4. 



mercury contact breaker, working at about one-half full power, was 

 employed, and when this coil was connected through two spark gaps to 

 the cathode C and the spare anode, the anti-cathode A being connected 

 to earth, the following phenomena were observed. 



With the anti-cathode so placed, as shown in fig. 4, that the cathode 

 rays impinged on its concave side at an average angle of about 135, in 

 addition to the slight general green fluorescence of about half the bulb, 

 due to the diffuse reflection of the incident cathode rays by the con- 

 cave anti-cathode, which fluorescence, as indicated in the illustration, 

 did not differ from what is usually observed in focus tubes, there 

 appeared two very bright and somewhat unstable fluorescent patches 

 upon the glass of the bulb facing the concave side of the anti-cathode. 

 One of these patches, E, which was approximately of circular form, 

 was directly opposite the concave side of the anti-cathode, and was 

 connected to the latter by a faintly luminous beam, while the other, F, 

 which was of a horizontally elongated form, had a position correspond- 

 ing with the extremity of a second luminous beam apparently of 

 cathode rays reflected from the anti-cathode in true specular fashion. 

 Further, on the glass facing the convex side of the anti-cathode, there 

 at the same time appeared a large-diameter hollow ring of very faint 

 fluorescence, GGT. 



On slightly rotating the anti-cathode in either direction, both the 

 patches and the ring were also found to move, the circular patch E, 

 and the ring GGT, maintaining a position respectively exactly in front 



