146 



Royal Society : — 



of the flake-like, which latter I have on that account called ele- 

 mentary striae. 



Elementary striae are in general produced at regular intervals . 

 along the tube. The series extends from the positive terminal in 

 the direction of the negative to a distance depending upon the 

 actual circumstances of the tube and current. The length of the 

 column, and consequently the number of the stria?, depends mainly 

 upon the resistance of the tube, the duration of the entire current, 

 and, to a certain extent, upon the amount of the battery- surface 

 exposed; and in that sense upon the strength of the current. 

 The velocity of the proper motion, other circumstances being the 

 same, depends upon the number of cells employed ; in other words, 

 upon the electromotive force. 



The appearances of the striae, however, their essential features, 

 and the conclusions which may be drawn from them will be 

 better apprehended by means of sketches, even though imper- 

 fect, than by meredescription ; and I therefore subjoin a few 

 examples. 



Fig. 1 represents the appearance of (in the mirror) a carbonic- 

 Fig. 1. 



m 



mm 



