ELECTRIC DISCHARGE WITH THE CHLORIDE OF SILVER BATTERY. 
91 
increase of pressure 1*250 to 1. The arc was also in this case crossed with close 
paper-like strata. 
Pressure 7 m.m., 9211 M, 11,000 cells, current 0*03138 W; appearance represented 
in Plate 9, fig. 9, from a photograph taken in 3 minutes. 
Pressure 60 m.m., 78,947 M, current not measured; represented in Plate 9, fig. 10, 
from a photograph taken in 1 minute. 
The arc in air between a point positive and a disc 6 inches distant is shown in 
Plate 8, fig. 31 ; pressure 56 m.m., 73,684 M, 11,000 cells, current 0'00993 W. The 
central spindle is curved and divided near the centre. 
Increase of pressure on making connexion with the battery of 11,000 cells, and 
producing a discharge between points 6 inches distant. 
Pressure. 
Depression. 
Ratio of 
increased to 
normal pressure. 
Current. 
M. 
m.m. 
W. 
10,526 
2-0 
1-25 
0-01771 
88,158 
22-2 
1-33 
not measured 
10,526 
2-5 
1-31 
7895 
1-5 
1-25 
0-03138 
The arc in air between two 'points at various distances and pressures with a constant 
number of cells. Temp. 12°*7 C. 
PLATE 8. 
11,000 cells, distance 0'54 inch, pressure atmospheric, current 0*02456 W ; the 
total resistance of battery and arc was found to be 461,500 oinns, that of the arc 
27,550, by substituting wire resistance ; whence the potential between the terminals 
was 657 cells. The appearance of the arc is shown in fig. 20 ; it exhibits clearly the 
tendency to break up into luminous entities ; the photograph of which this is a copy 
is nearly full size and was obtained in 20 seconds. All the other photographs are on 
a reduced scale. As the batteries were undergoing the annual overhauling, the number 
of cells, some being removed from time to time, was somewhat less in the following 
experiments, namely, 10,940. 
Pressure atmospheric 748*6 m.m., 985,000 M, distance 0*58 inch, current not 
observed, no depression of the mercury in the gauge was noticed ; indeed, it will be 
seen that at the higher pressures the depression is generally less than at the lower, up 
to a certain point. The arc is shown in fig. 1 from a photograph obtained in 10 seconds. 
Distance 0'58X 2 = 1*16 inch, pressure 294*9 m.m., 388,026 M, current 0'02881 W, 
depression 16 m.m., total pressure 294*9 — D 1 6 = 3 10*9 ; ratio of increased to normal 
pressure as P054 to 1. The arc is represented in fig. 2 from a photograph in 
N 2 
