Titanium, and Vanadium by Thermelectronic Currents. 281 



emissions. Now, since both the furnace temperature and 

 the intensity of the acting electric field will rise simul- 

 taneously when the heating current is increased, the 

 progressive developments of the two emissions will likewise 

 proceed simultaneously, and it is no doubt owing to this 

 fact that the composite character of the iron spectrum, as 

 given by an insufficiently protected alternating current 

 furnace, has escaped the attention of Dr. King. For, as 

 I have shown, with a well-protected continuous current 

 furnace, though the range of temperatures produced is the 

 same, the second emission, on account of the much feebler 

 electric field, manifests itself only at temperatures of over 

 5500° C. — namely, after the first emission has already 

 attained a high degree of development. And it is probably 

 thanks to the smaller electric field of my furnace that such 

 good agreement was found to exist between the furnace and 

 flame spectra of iron up to about 2500° C, because the 

 spectrum of this element as emitted by my furnace up to 

 this temperature was entirely caused by the action of heat 

 on a compound of iron under the sole control of the prevailing 

 temperature. 



§ 13. Summary of Results. 



1. The existence has been established of a new luminous 



phenomenon which manifests itself as a sharply defined 

 band, of pinkish hue, in the immediate vicinity of a 

 plate of graphite raised to a high temperature by 

 means of an electric current. The name red fringe 

 has been applied to this luminous band. § 4. 



2. It is shown that the red fringe is caused by an electric 



current, which is probably part of the heating current. 



3. The red fringe is not solely controlled by the plate 



temperature, for it can be made to appear or disappear 

 at will by the simple action of magnetic forces, without 

 altering the temperature. § 5. 



4. It is shown that the electric current underlying the 



formation of the red fringe is quite distinct from 

 thermionic currents, not only as regards sensitiveness 

 to the magnetic force, but also and particularly as to 

 the spectroscopic effects produced. In order to clearly 

 distinguish between the thermionic current and that 

 which gives rise to the red fringe, it is proposed to call 

 the latter the thermelectronic current. § 6. 



