Spectroscopic Study oj Electric Brush Discharge. 461 



current the heat communicated is much less than in the case 

 of the cathode. 



5. The anode fall alone is not able to account for the heat 

 energy communicated to the anode. 



The above work was done in the physical laboratory of the 

 University of Bristol, and I wish to record my thanks to 

 Dr. A. M. Tyndall for placing at my disposal the necessary 

 apparatus. 



Note. — Since the above paper was written it has come to the 

 author's notice that the result of Summary (1) was obtained 

 by Granqvist in a paper on cathode disintegration (Kon. Vet.- 

 Akad. For. Stockholm, 1898, No. 10, p. 726). 



L. A Spectroscopic Study of the Electric Brush Discharge- 

 in Water and Salt Solutions. By Harold Smith, M.Sc, 

 Research Student of Armstrong College *. 



[Plate V.] 





WHEN the various types of electrical discharge are 

 made to occur under the surface of liquids, and the 

 light examined with a spectroscope, it is found that the spectra 

 emitted are of quite a different character from the spectra 

 of the same discharges occurring in air. 



The electric arc burning under liquids has been the subject 

 of an investigation by Konen f. He found that the lines 

 were sharper, fainter, and with fewer self-reversals than was 

 the case with the arc in air. Moreover, he found that the 

 nature of the surrounding liquid had no influence on metallic 

 gSpectra, except in the case of very concentrated solutions of 

 barium and calcium salts. In these two cases the strongest 

 lines of barium and calcium appeared. 



The spark-discharge in liquids has been investigated bv 

 Wilsingt, Lockyer§, Hale ||, Konen t, and Finger ^[. It 

 was found that the nature of the liquid had no effect upon 

 the spectrum, except in the case of certain very concentrated 

 salt solutions, just as with the arc. Hale, using iron electrodes^ 

 also found that various salt solutions caused almost the whole 

 of the iron spectrum to be reversed. 



* Communicated by Professor Stroud, D.Sc. 



t Ann, der Phys. iv. 9. p. 742 (1902). 



X Astrophys. Journ. x. p. 113 (1899). 



§ Proe. Roy. Soc. lxx. p. 31 (1902). 



|| Astrophys. Journ. xv. p. 132 (1902). 



f Zeitschr. wis*. Phot. vii. pp. 329 and 369 (1909). 



