ME. T. ROYDS ON THE CONSTITUTION OF THE ELECTRIC SPARK. 
347 
It is to be observed that the spark described by Hemsalech in ‘ Comptes Rendus,’ 
142, 1511 (1906), was produced under very different conditions from mine, and that 
in it the negative luminosity did not travel into the spark gap. Walter, in ‘ Ann. d. 
Phys.,’ 21, 223 (1906), and Schenck, in ‘ Astrophys. Jour.,’ 14, 116 (1901), find that 
the streamers come from the negative electrode, and the former seeks to explain it as 
due to kathode disintegration. 
It would be an important acquisition to our knowledge if our views of the phenomena 
in the electric arc could be found to apply also to the spark, but I do not think that, 
the photographs support the suggestion.] 
PRESENTED 
8 AUG. 1308 
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