﻿152 Prof. Burton and ~Mv. Wiegand : Efect of 



Results. 



The photographs figs. 3 to 7 (PI. VI.), taken with an 

 exposure of one-fifth of a second, will give an idea of the 

 general phenomena observed as the potential of the brass ring, 

 visible in the photograph, was successively zero ffigs. 3 & 4), 

 + 160 volts (fig. 5), + 240 volts (fig. 6), and + 720 volts 

 (fig. 7). For low potentials up to about 20 volts the stream 

 varied little from that of figs. 3 & 4, while as the voltage 

 was increased the form shown in fig. 5 was reached at ;ibout 

 + 80 volts. The appearance was unchanged for increasing 

 voltages up to 160, and then it changed gradually, took the 

 form of fig. 6 at 240 volts : the spreading became more 

 pronounced (fig. 7) as the voltages were further increased up 

 to 700 or 800 volts and beyond. In case of each of figs. 4, 

 5, and 6 the stream was directed very slightly out of the 

 vertical ; for figs. 3 and 7 the stream was approximately 

 vertical. In the cases of figs. 4 and 5 the descending spray 

 was intercepted by an earth-connected metal plate, in order 

 to give an uninterrupted view of the ascending stream. The 

 details of pressure of water, size of nozzle, position of nozzle 

 with respect to inductor-ring, &c, were constant for all 

 these photographs. 



The following characteristics of the main stream in these 

 cases should be remarked : — (1) The natural uncharged 

 stream begins to scatter almost as soon as the drops are 

 formed ; on the original photographs the spraying of the 

 stream can be noticed almost immediately above the then 

 earth-connected brass ring : (2) with each of the charged 

 streams there is undoubted alignment of the drops making 

 up the stream. As later photographs will show, this 

 cannot be attributed to coalescence of the small drops on 

 collision, for instantaneous photographs show large and 

 small drops absolutely aligned in the main stream. In 

 fig. 5 the alignment is apparent to the very top of the 

 stream ; in fig. 6 the scattering takes place about two thirds 

 of the way to the top, while in fig. 7 much more violent 

 scattering takes place much earlier in the course of the 

 stream. The scattering in the last two cases undoubtedly is 

 due to the repulsion between the similarly charged drops, 

 as it increases in effect with increasing voltages. The 

 crucial point in the explanation of the phenomena is without 

 doubt the study of the forces bringing about the alignment 

 of the drops long before collisions come into plav. 



The rest of the photographs presented may be divided into 

 three groups, being instantaneous exposures at various parts 

 of the streams shown in figs. 3 to 7. 



