Ions produced by Rontgen Rays. 



73 



switch S to the switch F was then computed by means of the 

 formula 





CR log (l-JL 



loge 



where 



C = capacity of condenser ; 



q = charge received by condenser as measured by a 



ballistic galvanometer ; 

 E = potential of battery; 



<? = base of Naperian logarithms; 

 R = resistance in charging circuit. 



The values of t obtained in this way were aiso checked by 



means of a chronograph. 



The duration of the flash was obtained as follows : — 



In fig. 3 is shown the induction-coil, X-ray tube, and keys 



S and F, as in fig. 1, except that the key F is disconnected 



Fig. 3. 



entirely from the potential battery system and put in parallel 

 with a spark-gap Q, which is in series with the secondary of 

 the induction-coil and X-rays tube. Q is a brass connector 

 between the two halves of the secondary coil and connected 

 also to the primary coil for protection to insulation. This 

 brass connector was removed from one binding screw to a 

 distance of 05 millimetre. 



Since the connector Q is in series with the X-ray tube, a 

 spark will occur at Q simultaneously with the flash in the 

 tube unless the contacts of the key F are closed or so nearly 

 closed that the discharge takes place at F instead of at Q. 



