36 



applicable to the interpretation of fundamental 

 problems of physics, particularly those concerned 

 with the nature of radiation. The changes of 

 intensity of spectrum lines produced by raising 

 and lowering the temperature of the electric fur- 

 nace help to indicate how the shock of molecular 

 collisions may influence the motions of the elec- 

 trons within the atom. The phenomena of the 

 "tube arc" throw new light on radiation processes 

 hitherto associated mainly with high electric po- 



FIG. 28. Electric Furnace. 



tentials. The complex phenomena of the Zeeman 

 effect (as revealed in a comparative study, with 

 powerful spectrographs and an intense magnetic 

 field, of the lines of a long list of elements) furnish 

 material available for wide generalizations, impor- 

 tant in their bearing on theories of radiation and 

 atomic structure. Thus the maintenance of this 

 laboratory would be highly advantageous from 

 the standpoint of the physicist, even if it had no 



