42 Colorado College Studies. 



I. The limiting conditions attending the observation of 

 the phenomenon. 



II. A comparison of the ease of manipulation and range 

 of the two methods. 



III. Whether at different temperatures the magnetic 

 effect is radically different. 



IV. To measure the magnetic shift {i. e., change of wave- 

 length) of the spectral lines examined, and to determine the 

 ratio e/m. Also to observe the state of polarization of the 

 components. 



In the study of parts I., II. and III. the sodium flame and 

 sodium in a vacuum tube w^as made use of. The conclusions 

 reached were as follows: 



I. (1) The magnetic shift of the sodium lines J) J) 2 as 

 given by a naked flame, caimot, with the spectro- 

 scope method, be distinctly observed at the tempera- 

 ture of the Bunsen flame, nor of the air-blast flame, 

 nor at the temperature of the oxy-hydrogen flame, 

 unless precautions are taken against spontaneous 

 reversals. 



(2) The phenomena can be better observed parallel to 

 the magnetic field than perpendicular to it, as the 

 strength of field necessary to produce a pure {i. e., 

 visual) triplet is twice that necessary to produce 

 the doublet. 



(3) There is a very perceptible time lag both when the 

 magnet is excited and when the current is broken, 

 during which time the spectral lines show an inertia 

 effect. The time lag does not seem to be wholly due 

 to the self-induction of the magnet, but may be par- 

 tially due to persistence of vision and partially to 

 ionic inertia. 



(4) A field strength of at least 15,000 C.G.S. units 

 seems to be necessary for satisfactory observation, 

 and spectra above the second order are too faint 

 for good effects. 



