344 Trowbridge — Electric Discharges through Hydrogen. 



views of a mind not biased by ionization theories would appear 

 to be supported by the phenomena presented by the tube rep- 

 resented in fig. 5. 



One branch of this tube is at right angles to the other 

 branch. There are two anodes, A and A', and two perforated 

 cathodes, K and K'. When a multiple circuit is formed by 

 leading in the current to the two anodes and out by one 

 cathode, K, striae form in the branch A'K' after they disappear 

 in the branch AK ; and they persist in A'K', when the 

 branch AK appears to be nearly at the X-ray stage. One 

 looking at the branch A'K' would suppose that the rarefac- 

 tion of the entire tube was low ; and gazing at the branch AK 

 w T ould think it very high. The bend in the tube acts like a 

 magnet in allowing the striae to emerge from the anode A' ; 



Fig. 5. 



and it does this by enfeebling by reflection the effect of the 

 cathode rays in the branch A'K'. 



The function of the cathode beam seems to be twofold ; it 

 forces back the striae ; and at higher exhaustions it ionizes the 

 gas ; for the current ceases to flow at high exhaustions when the 

 cathode beam is strongly diverted by a magnet. These func- 

 tions are illustrated by the phenomena in a tube represented 

 in fig. 6. 



Between the anode, A, and a cathode, D, the glass tube is con- 

 stricted. The cathode D is a circular disc with an orifice a 

 little larger than the glass orifice. The cathode rests upon the 

 walls of this orifice, presenting no metallic surface toward the 

 anode A. The cathode beam produces fluorescence toward D' 

 and is marked in the direction toward A by a white beam 

 which produces hardly a perceptible fluorescence. The latter 

 beam does not come from the metallic surface of the cathode ; 

 but seems to come from the gas in the region DD ; . At com- 



