iUb ■ MESSRS. W. DE LA RUE AND H. W. MULLER OR THE 
Pressure 15 m.m., 19,737 M, 11,000 cells, current 0-03071 W. A spindle-shaped 
luminosity at the positive about l-l inch long, and the negative ring completely 
surrounded with a glow which had increased considerably since A. After a short 
time the spindle on the positive lengthened out and nearly reached the negative, 
hugging the underside of the tube, as in B, fig. 87. It was not sensitive to the 
approach of the finger, although close to the glass ; 6300 cells produced the same 
phenomena. 
Fig. 87. 
Pressure 13 m.m., 17,105 M, 11,000 cells, current 0’01772 W. At the positive, a 
spear with a staff not greatly exceeding the diameter of the wire, the spear-head reach¬ 
ing to the middle of the tube. The glow on negative less brilliant than the preceding 
phase in consequence of a less current passing. 
Pressure 9 m.m., 11,842 M, 6,300 cells, current 0‘02693 W. A well-formed 
arrow-like luminosity at the positive, the negative ring three parts illuminated. 
After a while the luminosity shot forward towards the negative and lost its arrow 
shape, and then retreated to the positive, assuming the form of a long pear. 
Pressure 8 m.m., 10,526 M, 6300 cells, current 0‘01772 W. A long discharge 
reaching to the middle of the tube, in the centre of which was a very bright 
wire-like luminosity like that in A, fig. 87, which in the latter case was attached to 
the positive. 
