272 CARNEGIE INSTITUTION OF WASHINGTON. 



A current of oxygen, passed through the electric-furnace tube, gives 

 a means of producing flame spectra over a wide range of temperatures, 

 the maximum temperature probably being higher than that obtained 

 in the regular flames. 



A study of anomalous-dispersion phenomena has been made with 

 the electric furnace, both with regard to general effects and to the 

 possible change of wave-length of a line very close to another line which 

 shows strong anomalous dispersion. These tests and the use of mixed 

 vapors in the furnace gave no evidence of the predicted repulsion 

 between close lines. 



The complex lithium line X6708 has been photographed with high 

 dispersion in furnace and arc spectra and its components have been 

 measured. The close agreement with the wave-length of a prominent 

 sun-spot line offers evidence of the presence of lithium in the solar 

 atmosphere. 



Preliminary experiments have shown the possibility of bringing 

 metallic vapors to luminescence by the impact of cathode particles in 

 high vacuum. 



Additional measures of the Zeeman efTect have been made for 

 2,388 lines in the spectra of Fe, V, Cr, and Ti. 



Interferometer determinations of wave-length with respect to the 

 red cadmium line have been partially completed for loO iron lines in 

 the region XX 4100-5050. 



Tests of the 100-inch mirror, now completed and silvered, show a 

 maximum error of focal length for any zone of about one part in 92,000 

 as compared with the theoretical value. 



The 100-inch reflector dome has been completed and painted, and 

 over one-half of the mounting is erected. The observing-platform. 

 10-ton traveling-crane and cage hoist, shutter mechanism, and jib crane 

 have been installed, together with a portion of the mirror elevator. 

 The Snow telescope has been remodeled for use in conjunction with a 

 vertical spectrograph of 30 feet focal length, for which the pit has been 

 completed. About 900 feet of concrete conduit for electric wires have 

 been constructed, a portion of which contains the heavy cables furnish- 

 ing power to the 100-inch telescope and dome. Many test rulings and a 

 preliminary grating of very promising quality have been made wath the 

 ruling engine. 



