650 BELL SYSTEM TECHNICAL JOURNAL 



formation was found to alter the secondary emission coefificient of 

 nickel by less than 0.3 per cent. The temperature coefficient of 

 secondary emission, in the cases of nickel, cobalt, and molybdenum, 

 was found to be much less than the volume coefficient of expansion of 

 the metal. The smallness of the temperature coefficient and the effect 

 of the magnetic transformation are shown to lend support to the view 

 that the secondary electrons are scattered or "absorbed" by an 

 excitation process similar to that whereby they are originally produced. 



