Proceedings of the American Academy of Arts and Sciences. 

 Vol. XXXVIII. No. 10. — November, 1902. 



THE INFLUENCE OF ATMOSPHERES OF NITROGEN 

 AND HYDROGEN ON THE ARC SPECTRA OF IRON, 

 ZINC, MAGNESIUM, AND TIN, COMPARED WITH THE 

 INFLUENCE OF AN ATMOSPHERE OF AMMONIA. 



By Royal A. Porter. 



ISVESTIOATIONS ON LlGflT AND IIeAT, MADE AND PUBLISHED WHOLLY OR IN PART WITH APPROPRIATIONS 



FROM THE KUMFORD FUND. 



