Nipher—On the Nature of the Electric Discharge. 63 
towards the grounded terminal in a more strongly 
marked way. It certainly might be expected that some 
such effect might exist in case of a disruptive discharge. 
Fig. B of Plate XXIII was exposed in the positive line 
in precisely the same way that former plates were ex- 
posed in the negative line. Here the negative discharge 
comes from the ground. The ionization is produced at 
the positive pin-head terminal, which is connected with 
the positive terminal of the machine. 
In Fig. C of Plate XXIII the pin-head terminals were 
connected with the + and — terminals of the machine. 
The spark-gaps at the machine were not more than 3 or 
4mm. A single spark was passed through these gaps. This 
figure shows what is clearly shown in other plates, how 
insignificant is the ionizing effect at the negative termi- 
nal, as compared with that which produces the negative 
inflow at the positive terminal. In fhis plate these ioni- 
zation effects are due to the exhaust effects at the posi- . 
tive terminal and to the presence of the negative termi- 
nal, which produces such effects at the opposite terminal, 
even when it is grounded. The effect is to be finally 
traced to the forced rotation of the glass plates of the 
machine in the presence of the inductor cards on the sta- 
tionary plates 
In this figure it will be observed that one of the stream 
lines which proceeds to the positive terminal curves 
around the small black area at the negative terminal. Its 
source is on the opposite side of the negative terminal 
from the positive terminal. Its curved form is due to the 
negative outflow from the negative terminal. 
In .this figure as well as in Fig. A of Plate XXI the 
discharge lines have a form which suggests lines of force 
from static charges of opposite sign. It is, however, to 
be observed that the conditions in these fields of force 
are dynamic in character. There is an outflow of gaseous 
molecules from both terminals, as will be explained later. 
The meeting and mingling of these oppositely directed 
‘electric winds,’’ produced the disturbed condition that 
is to be observed between the terminals and just outside 
