14-i Trowbridge — Magnetic Field to X-ray Tithes. 



of producing the X-rays from a sharp focus and should, there- 

 fore, give better definition. 



It may be urged that the amount of energy employed in 

 exciting the magnetic field could, with equal advantage, be 

 added to that which excites the tube ; but this would result in 

 possible strain or danger to the tube and would not result in 

 bringing the stream to a sharp focus. The large bulb need 

 not be blown thin and, therefore, the danger of perforation 

 can be greatly lessened ; moreover, the application of the mag- 

 netic field serves as a rectifier, and when a Leyden jar is used 

 it allows only the oscillation from the cathode to reach the 

 focal plane. 



Jefferson Physical Laboratory, Harvard University. 



