58 



Trans. Acad. Sci. of St. Louis. 



part a disruptive spark discharge. This is accompanied 

 by a streaming in of the negative fluid from various 

 directions over the film. See Plate XVIII, Fig. B, and 

 Plate XIX, Fig. A. In the negative line the copper plate 

 is in the case shown in Fig. 1 energized by a compression 



o 



Fig. 1. 



action from the machine terminal. The discharge from 

 the film is urged towards and into the grounded line. 

 The flow lines resemble a system of rivers and tributary 

 streams. 



In the positive line the terminal resting on the film is 

 in a condition which may be described as an exhaust con- 

 dition. The electric fluid is then drawn into the pin-head 

 terminal from the film. The stream lines in this case 

 certainly originate at the pin-head terminal, and elongate 

 in a direction opposite to that of the flow. Possibly this 

 may be true of the plate in the negative line also. The 

 results seem to be alike in character. The action is, how- 

 ever, different, and it may be that there is a difference in 

 degree. There is in both cases a condenser effect. In 

 Plate XVIII, Fig. A, and Plate XIX, Fig. B, are shown 



