228 Mr Orange, On certain phenomena of the kathode i^egion. 



The inconvenience of the apparatus in the respect mentioned 

 above was amply compensated for by the ease with which the 

 region could be viewed in other directions (that is to say, in hori- 

 zontal directions). Of the appearance in one of these directions, 

 viz. that showing the kathodes lengthwise, there is little to say. 

 Fig. 6, Plate IX, shows the one stage of any interest ; the form of 

 the Crookes' dark spaces in the kathodic interspace is peculiar, 

 but it seems to be quite in accordance with the views previously 

 stated. 



Examination of the region in the remaining principal direction 

 revealed much more interesting features (Pis. VII and VIII), and 

 what follows refers entirely to appearances viewed in this way. (i.e. 

 by looking horizontally so that the line of sight is parallel to the 

 longest sides of the kathodes, these longest sides lying to the left, 

 while the obtuse angles of course fall on the right.) 



The photographs cited are selected from a large number of 

 records taken. In Figs. 2 and 7, PL VIII, the positive column in- 

 trudes but does not seriously mar the view; it would appear to have 

 no direct connection with the phenomena discussed in this paper. 

 The Crookes' dark spaces are in all cases clearly defined, and it is 

 noticeable that while they are still unfused, as in Figs. 1, 2 and 6, 

 PI. VII, the thickness of the dark space is greater opposite the 

 remote faces of the kathodes than it is over the interfaces. 



The striking feature, however, in most of this series, is the 

 distribution of kathode rays in the form of a very sharply-defined 

 cross of St Andrew's. The pencils are especially well defined on 

 the left side, that is in connection with the longest sides of the 

 triangles. On the right some slight confusion occurs owing to the 

 way in which this part of the triangle is viewed. The system of 

 rays really forms two sheets, somewhat like slightly truncated 

 pyramids, the base of the lower one being visible at the lowest 

 pressures as a phosphorescent trace which encircles the bulb like 

 a line of latitude (Figs. 2 and 7, PI. VIII). The pencils are 

 remarkably restricted transversely at the lower pressures, e.g. 

 Fig. 7, and, moreover, they pursue a slightly curved path. In 

 all cases where the two Crookes' dark spaces either adjoin each 

 other or are fused together, kathode rays are also emitted abun- 

 dantly along the median plane of the interkathodic space, e.g. 

 Fig. 1, PL VIII. 



I think we may correlate the oblique rays with a phenomenon 

 described by Kunz*. Kunz used as kathode a hollow cylinder and 

 observed on the containing vessel phosphorescent rings opposite 

 the mouths of the cylinder. If the rays described above correspond 

 to those producing Kunz's rings, then the latter's explanation 

 of the phenomenon must be wrong, as a reference to his diagram f 

 will show. 



* J. Kunz, loc. cit. pp. 164 et seq. t Ibid. p. 170. 



