194 PROCEEDINGS OP THE AMERICAN ACADEMI 



cursions away and toward the slit, and therefore no displacement of 

 the spectrum lines was to be expected. 



The photographic plate was exposed in the neighborhood of the great 

 H lines. A movable shutter enabled me to expose different portions 

 of the same plate without changing any adjustments of the apparatus. 

 The resulting photograj^hs showed no displacement of the iron lines. 

 The iron lines in the two photographs met exactly, continued in an 

 unbroken line across the double photograph, and were of the same 

 breadth throughout their extent. 



The conclusion seems to be a strong one, that the electrical oscilla- 

 tions do not carry the atoms of metals with them in spark discharges. 

 The atom is merely shaken up, and caused to emit the vibrations or 

 subsidiary ripples which appeal to our senses as light and heat, while 

 the electrical waves pass on without conveying the atoms. 



Jefferson Physical Laboratory. 



