ELECTRIC DISCHARGE WITH THE CHLORIDE OP SILVER BATTERY. 215 
tube, both pumps, and the McLeod gauge to a pressure of 410 m.m., 539474 M, thus 
showing that it was capable of absorbing a large volume of gas. 
211. — The tube was now exhausted, first with the Alvergniat pump, which was 
subsequently shut off at the cock C, fig. 35, afterwards with the Sprengel, 
the cock between the absorption chamber and the tube being left open. 
When the pressure had reached 0'005 m.m., 6' 5 8 M, the current of 11,000 
cells would pass only when the straight wire was negative. When the 
pressure was 0‘00137 m.m., 1'8 M, the current would not pass in either 
direction. The exhaustion and absorption were carried on until the pressure 
fell to 0'000055 m.m., 0'066 M, at which pressure there was, of course, no 
current. The Apps’s induction coil 821, set to produce a 1-inch spark, would 
not pass at first, but did so after the current had been made to pass with a 
6-inch spark. The pressure rose to 0'0024 m.m., 3'2 M. 
212. — Exhaustion to 0 ’000 16 m.m., 0'2 M, having been again obtained, the 
absorption chamber was shut off, and a charge of gas from the calibrated 
tube, the capacity of which is ^oo that of the main tube, was let into 
the tube and Sprengel pump ; it increased the pressure to 0'226 m.m., 
giving 04-9-Q for the ratio of the capacity of the calibrated chamber to that of 
the tube plus the Sprengel pump and McLeod gauge. When the gas was 
let in the current of 11,000 cells, 0 '04201 W, immediately flashed through 
the tube, and produced twenty blue strata, like those in fig. 9, Plate 16, 
reaching to within 7 inches of the negative. 1200. cells gave a current 
0'00580 W, and produced nineteen grey strata, the concave face of that 
nearest the negative being pink. 
213. — The absorption chamber was now opened, and in about five minutes the 
pressure was reduced to 0'0268 m.m., 35 M. 11,000 cells, C. 0'01102 W, 
produced nine milky broad strata, like those in fig. 12, Plate 16. In 45 
minutes the pressure had decreased to 0'00137 m.m., 1'8 M. and 11,000 cells 
would not pass. 
214. — Two charges let in ; pressure 0'435 m.m., 571 M, 1200 cells, C. 0'00993 W, 
twenty-two pink strata as fig. 5, Plate 16 ; 2400 cells, C. 0'02634 W, 
rendered the strata blue, and like fig. 4 of the same Plate. 
215. — Third charge, pressure 0'6423 m.m., 844 M, 2400 cells, C. 0'02776 W. 
216. — Fourth charge, pressure 0'8968 m.m., 1180 M,. 2400 cells, C. 0'02925 W. 
twenty-four blue strata, like fig. 4, Plate 16. 
217. — Fifth charge, pressure 1T294 m.m., 1486 M, 2400 cells, C. 0'02925 W. 
twenty -two blue and. very deep cup-shaped strata. 
218. — Sixth charge, pressure 1'396 m.m., 1836 M, 2400 cells, C. 0'02850 W. An 
agitated stratification of tongues crossing each other and producing a kind 
of X form. The C and F lines, which had been faint in the other phases, 
were bright in the negative glow, but not in a stratum. 
