257 



Table 2. 





Voltage before 







Speed 



Magnet 



Voltage with 



Type of discharge 



was axcited 



Magnetism 



Effect of Magnetism on form of discharge 



1 



21500 



21500 



Glow. 



2 



22000 



21850 



Small brush. 



3 



22500 



22000 



Occasional spark. 



4 



20000 



22500 



Changed to brush by magnetism. 



5 



22500 



22500 



No change. 



6 



20000 



22500 



Changed to brush. 



7 



18800 



26500 





8 



18800 



24000 



" " 



9 



18800 



23500 





10 



18800 



18800 



No change. 



11 



18150 



25000 



Changed to brush. 



11 



18150 



18150 



Not changed to brush. 



12 



18150 



18150 



No change. 



13 



18150 



24000 



Changed to deflected scattered sparks. 



U 



18800 



25000 



Changed to brush. 



15 



18800 



24000 



Scattered deflected sparks. 



16 



18500 



25000 



Changed to brush. 



The above table sbows that there is no i-egulai'ity in the changes in 

 the discharge due to the influence of the magnetism. In No. 11 the spark 

 discharge was entirely changed to brush for a while, then broke into a 

 spark again, changing sometimes two or three times per minute. When the 

 exciting current was stopped the sparking was again resumed. In the many 

 complete sets of readings similar to the above it was found that this change 

 appearing in No. 11 occurred for any of the spark discharges, but the actual 

 condition that caused it was not discovered. One could not foretell when 

 the discharge would be altered by the influence of the magnetism. Series 

 Hj shows photographs of the same sort of discharge as Hi, in which there 

 was no change due to magnetism. These were taken twenty-four houi's 

 later than those of Hi. and on this particular day no change occurred in the 

 discharge, when tlie current was in the direction shown in H,., while on the 

 previous day, with the same conditions in so far as apparatus was con- 

 cerned, the spark was changed to brush every time the exciting current was 

 closed, regardless of the direction of the magnetism. In series H, the 

 spark was changed to brush by the magnetism when the other point was 

 made positive, the photograjihs being like the corresponding ones of 

 series Hi. 



117—26988] 



