192 Trowbridge — Magnetic Field and Coronal Streamers. 



from 5 to 20 centimeters, 3000 to 8000 volts in wide tubes, 

 streamers radiate from the position of the magnetic .pole. 

 Fig. 3 is a photograph of such streamers or stratifications. It 

 will be noted that these striae make their appearance at a much 

 higher pressure than that of the usual striae in raritied gases. 



Electric discharges around or toward the poles of the sun 

 transverse to the lines of magnetic poles of the sun could be 

 separated into streamers. 



Effect of a Magnetic Field on the Production of X- Rays. 



The ordinary form of X-ray bulb does not lend itself 

 easily to the application of the magnetic field, either at the 

 anode or the cathode, and even in the special form of bulb, 

 fig. 4, which I have used in this investigation, it was not possi- 

 ble to develop magnetic lines of force over the entire surface 



4 





of anode or the cathode. The cores of the electromagnets 

 were hollow in order to allow of the approach of the coil of 

 the electromagnet to the terminals of the bulb, the glass seals 

 of these terminals thus projecting into the hollow iron cores; 

 only a circular area, .therefore, on the cathode or anode forms 

 the effective magnetic field. It seems probable that the best 

 results would be obtained by enclosing the iron core entirely 

 inside the bulb, platinizing the end of the iron core forming 

 the anode, placing the aluminum mirror forming the cathode 

 directly in the end of an iron core and nickel plating both 

 iron cores to prevent the constant escape of gases from 

 such large surfaces of iron. I had a bulb of this general 

 description constructed, but found it impossible to exhaust 

 it to the X-ray stage on account of the escape of gases from 

 the iron; the iron was not nickel plated, however. The bulb 

 was exhausted while it was strongly heated in an oven. 



Fig. 5 is a photograph of the discharge in the X-ray 

 bulb somewhat before the X-ray stage ; a dark space surrounds 

 the cathode. 



Fig. G is a photograph of the same tube when the mag- 

 netic field is applied to the anode. This cone of rays is 



