THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



- 5 ^[MXTH SERIES.] 



MARCH 1920. 



XXV. On the Excitation of the Spectra of Carbon, Titanium, 

 and Vanadium by Thermelectronic Currents. With special 

 Reference to the Cause of Emission of Light Radiations by 

 Luminous Vapours in the Carbon Tube Resistance Furnace. 

 By G. A. Hemsalech *. 



[Plates II.-V.] 



Contents. 

 § 1. Introduction. 

 § 2. Experimental methods. 

 § 3. Temperatures of graphite plate for various potential gradients of 



heating current. 

 § 4. Luminous phenomena observed in the vicinity of an electrically 



heated plate of graphite. Bluish vapour and red fringe. 

 § 5. Influence of a transverse magnetic field upon the visibility of the 



red fringe. 

 § 6. Origin of the red fringe. Thermelectronic current. 

 § 7. Spectroscopic analysis of the red fringe and luminous vapours. 

 § 8. Cause of the sharp outline shown by the red fringe and of the 



abrupt cessation of its spectrum emission. 

 § 9. Displacements of red fringe emission by transverse magnetic fields. 

 § 10. Possible cause of excitation of red fringe spectrum. 

 § 11. Discussion of results and their application to the case of the electric 



tube resistance furnace. 

 § 12. Probable cause of disagreement between Dr. King's results and 



mine. 

 § 13. Summary of results. 

 § 14. Concluding remarks. 



* Communicated by the Author. 

 Phil. Mag. S. 6. Vol. 39. No. 231. March 1920. R 



