OF ARTS AND SCIENCES. 521 



the Academy at the Annual Meetinj]; the award of the Rumforti INIedal 

 to Professor Carl Barus, of Brown University, for his various researches 

 in heat. 



In response to the usual request, the Chairman of the Committee has 

 received reports of progress from the following persons to whom grants 

 have been made from the Rumford Fund : Professors H. Crew, 

 E. B. Frost, G. E. Hale, E. H. Hall, F. A. Laws, E. L. Nichols, 

 E. C. Pickering, B. O. Peirce, T. W. Richards, and W. C. Sabine. 



These reports in full or in abstract are presented as an appendix to 



this Report. 



Chas. R. Cross, 



Chairman of the Rumford Committee. 

 APPENDIX. 



Reports of Progress to the Rumford Committee. 



May, 1900. 



PROFESSOR HENRY CREW. 



Grants of October 20, 1896, $400, for researches on the electrical, 

 chemical, and thermal effects of the electric arc, and May 3, 1899, $200, 

 for researches on the spectrum of the electric arc. 



Referring to an "air-tight arc" which he has constructed, Professor 

 Crew says, " This apparatus is well made, and works in a thoroughly 

 satisfactory manner. With it I have made several series of photographs 

 of the arc spectra of iron and magnesium, in an atmosphere of pure 

 hydrogen. These plates I am now measuring up, and hope to be able 

 to publish the results during the coming summer. 



" Contrary to expectations, I do not find the iron spectrum at all 

 simplified by the introduction of hydrogen. For while many lines are 

 blotted out, many new ones are introduced by the hydrogen. No less 

 than sixty-two iron lines, either new or profoundly modified, make their 

 appearance between X. 2753 and A 4415. The origin of these lines I 

 have not yet succeeded in finding. 



" I have spent some time also in trying to produce, in this arc, the 

 hydrogen series discovered by Professor Pickering in the star Z Puppis ; 

 but I have not found anything resembling such a series." 



PIIOFESSOR EDWIN B. FROST. 



Grant of January 10, 1900, $500, to assist in the construction of a 

 spectrograph, especially designed for the measurement of stellar velocities 

 in the line of sight. 



