2 ".V RAYS 



as I used in my researches on the velocity of 

 propagation of " X " rays, might perhaps in this 

 case play the part of analyzer, inasmuch as the 

 properties of a spark may be different in the 

 direction of its length, which is also that of 

 the electric force producing it, and in directions 

 normal to its length. Starting from this, I 

 arranged an apparatus as shown in the accom- 

 panying diagram, so as to obtain a small 

 spark during the emission of " X " rays. 



A focus tube is connected to an induction- 

 coil by wires BH, B'H', covered with gutta- 

 percha (Fig. i). Two other wires, also covered 

 with gutta-percha, Air and A'lr', terminate at A 

 and A 7 in two loops, which surround BH and 

 B'H' respectively ; a bit of glass tubing, not 

 shown in the figure, keeps each loop separate 

 from the wire which it surrounds. The wires 

 AI, A'l are then twisted together, and their 

 sharply pointed ends, c and c\ are fixed 

 opposite each other, at a very small distance, 

 adjustable at will, so as to form a small spark- 

 gap. By virtue of this disposition, the 

 electrostatic influence exercised by the wires 

 BH and B'H' on the loops A and A' produces 



