ON THE NATURE OF THE ELECTRIC DISCHARGE 
THE ONE-FLUID AND THE TWO-FLUID 
: THEORIES.’ 
FRANCIS E. NIPHER. 
The dissymmetry in the discharge effects at the posi- 
tive and negative terminals of an electric machine is now 
ascribed to the difference in the size of the carriers of the 
electric discharge. In my former paper in these 'l'rans- 
actions evidence has been presented, which shows that 
this dissymmetry is due to the fact that the negative 
electrons are being forced out under ‘‘pressure’’ at the » 
negative terminal, and that they are being drawn in 
at the positive terminal under conditions which may 
be likened to those on the exhaust side of a pump. 
Characteristic forms of discharge lines usually attrib- 
uted to positive and negative discharge are shown 
in Plates XVIII and XIX, Figs. A and B. 
Such plates were obtained by means of the arrange- 
ment shown in Fig. 1. 
The lines leading from the terminals of an influence 
machine are separately grounded in the yard outside 
of the building. In each line there is a spark-gap of sev- 
eral centimeters at the machine terminal. Each line has 
another gap, the two ends of which terminate in pin- 
heads which make a spring contact with copper plates 
P and P1. The copper plates rest on sheets of glass. 
The pin-head nearest the machine in the positive line, and 
the one nearest the ground in the negative line are in 
Fig. 1 shown as resting on the film of a photographic 
plate. The other pin-heads rest on the copper sheets. 
In each case there will be an inflow of Franklin’s fluid 
from the copper plate to the pin-head. This inflow is in 
1 Continued from No. 1, Vol. XIX. Presented before The Academy 
of Science of St. Louis, May 2nd, 1910. 
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