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HON. R. J. STRUTT ON THE LEAST POTENTIAL DIFFERENCE, ETC. 



effected in some radically different way. But these curves show that the behaviour of 

 helium when conveying the discharge, though very peculiar, is not radically different 

 from that of the common gases. 



In conclusion, I must record my best thanks to Professor J. J. THOMSON. I cannot 

 adequately express how much I owe to his kind encouragement and advice. 



