338 Adeney — Photographs of Sparlt Spectra from the Rowland Spectrometer. 



In conclusion, the author begs to express his sincere thanks to Professor W. N. 

 Hartley, f.k.s., for mucli advice and assistance kindly afforded by him in the 

 preparation of this communication. The author is also indebted to Professor 

 Hartley for the electrodes of iron, nickel, and cobalt employed in this research, 

 and also for allowing him free access to his private collections of spectra and 

 instruments. 



