ELECTRIC DISCHARGE WITH THE CHLORIDE OF SILVER BATTERY. 107 
Pressure 5 m.m., 6579 M, 6300 cells, current 0 - 02693 W. 
Pressure 4'5 m.m., 5921 M, 6300 cells, current 0'03657 W. 
Pressure 4 m.m., 5263 M, 6300 cells, current 0‘03459 W. The discharge in. the 
latter case was partially stratified. 
Pressure 3 m.m., 3947 M, 6300 cells, current 0'04474 W. Similar phenomena to 
those at a pressure of 4 m.m., except that the negative glow was more extended and 
terminated in a fringe-like contour composed of filaments of light. 
Pressure 3 m.m., 3947 M, 6300 cells, current 0 - 04901 W. Two stratified lumino¬ 
sities as shown in Plate 9, fig. 6, copied from a dry-plate photograph _ obtained in 
25 seconds, and a drawing made at the time; the negative was completely and very bril¬ 
liantly illuminated. After a short time the two luminosities coalesced to form one at 
the positive terminal, and between it and the negative there was a long dark discharge. 
The outer boundary of the discharge from the positive is less bright than the fluores¬ 
cent glow of the tube, as was the case with a discharge in air. Plate 10, fig. 19, 
shows the phenomena of the discharge in tube 200 at the same pressure, with a current 
of 0'03071 W; this exemplifies well the influence of the diameter of the tube on the 
phenomena of stratification. In fact, in tube 199 we have not yet succeeded in 
obtaining a steady stratification, while in tubes of a less diameter perfectly steady 
strata are always obtained, although their form and number depend partly on the 
dimensions of the tube, Part II., fig. 62a, p. 209. 
Pressure 2 m.m., 2632 M, 6300 cells, current 0'04686 W. Strata for three-fourths 
of the length of the tube, commencing at the positive in a point and enlarging to 
about half the diameter of the tube as it approached the negative. 
Pressure 1*5 m.m., 1974 M, 6300 cells, current 0‘05801 W. The strata completely 
filling the tube towards the negative in form like C, fig. 87. The negative still more 
brilliantly illuminated, the glow terminating as a fringe. The resistance of the tube 
was found to be 63,000 ohms. 
Pressure 0'5 m.m., 657 M, 4800 cells, current 0 - 03657 W. The discharge was as in 
Plate 9, fig. 7, copied from a dry-plate photograph obtained in 25 seconds. The 
glow around the negative completely filled the tube as if the discharge experienced 
difficulty in emanating from that terminal, and that the gas was driven with force 
against the inner wall of the tube. We have already alluded in Part II. to the 
projection of matter from the negative terminal in a direction normal to its surface, 
and not necessarily towards the positive ; Gassiot* has recorded similar phenomena, 
and Crookes’ remarkable researches have shown in the most convincing manner 
that this occurs, and that the matter projected may be brought to a focus by curved 
surfaces. 
The great extent of the dark discharge which sometimes obtains is very remarkable 
and requires special study. We have stated in Part II., p. 157, &c., that the strata some¬ 
times thread themselves completely on the negative terminal, and that after a time they 
* Part II., Appendix, Note C. 
p 2 
