148 Royal Society: — 



fined towards the positive. The following description of the phe- 

 nomena, taken from my earlier notes, may now be regarded as a 



Fie. 2. 



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description of the apparent proper motion of the flocculent as 

 distinguished from the elementary striae : — " The discharge opens 

 with a considerable rush, indicated by the bright line at the com- 

 mencement. There is no other indication of partial discharges. 

 Proper motion at first towards the negative, afterwards towards 

 the positive terminal. In this, as in other tubes giving striae of 

 this kind, ripples may be observed on the curve of proper motion." 

 So far my older notes ; but on closer examination, and when 

 the battery- surf ace exposed is sufficiently reduced, the entire field 

 is seen to be traversed by elementary striae having a normal proper 

 motion. When the battery-surface is gradually increased, the 

 elementary striae, especially near the head of the column, have 

 their duration shortened so as to leave dark intervals at r >gu!ar 

 stages in the column. These successive short-lived elementary striae 

 form a series of diagonal lines, each series of which traces a 

 sketch of a flocculent stria. As the surface is still further in- 



