232 CARNEGIE INSTITUTION OF WASHINGTON. 



bardiiig a vapor with a stream of cathode particles, promise to be 

 of interest when studied quantitatively (p. 260). 



The measurement of secondary standards of wave-length by inter- 

 ference methods, in teniis of the red cadmium hne, has advanced rapidly 

 since the installation of the auxiUary concave grating and the perfected 

 quartz-invar etalons. The use of several fonns of arc, in air and in 

 vacuo, the eUmination of displacements due to ''pole-effects" and 

 pressure, and the application of powerful grating spectrographs to 

 check the interference results, should yield international secondary 

 standards of the highest attainable accuracy (p. 260). 



The further study in the laboratory of the Zeeman effect has pro- 

 vided a large collection of new data for the spectra of iron, chromium, 

 vanadium, and titanium (p. 260). Corresponding studies of the 

 Stark effect have yielded new results for lithium and calcium (p. 239). 

 Both investigations are being extended to other elements. 



On the instrumental side, the work of the year has been devoted 

 largely to the completion of the ruling machine and the extensive labor 

 of finishing, transporting, and erecting the 100-inch telescope. The 

 successful outcome of the long task of figiu'ing the 100-inch mirror, the 

 production of an excellent grating, and the accomplishment of the work 

 of transporting most of the heavy and cumbersome parts of the tele- 

 scope up Moimt Wilson, where they are now being erected, mark the 

 beginning of the last stage in the provision of the equipment originally 

 planned for the Observatory. The excellent figure of the large mirror 

 is a source of special satisfaction, which we trust may be augmented 

 in the near future through the actual use of the 100-inch telescope 

 (p. 264).^ 



STAFF. 



During the first half of the year the Director continued his solar 

 researches in collaboration with several members of the staff. In 

 April he was called upon by the National Academy of Sciences to assist 

 in the organization of a National Research Councdl. This task, 

 undertaken at the request of President Wilson, has occupied most of 

 his time since that date. Dr. Walter S. Adams, Assistant Director, 

 has continued to direct the investigations in stellar spectroscopy and 

 has had general charge of the Observatory during the Director's 

 absence. Professor Frederick H. Seares, superintendent of the 

 Computing Division and editor of the Observatory publications, has 

 carried on his researches in stellar photometry, the determination of 

 the position of the sun's magnetic axis, and other subjects. Dr. 

 Arthur S. King, superintendent of the Physical Laboratory, has 

 devoted most of his time to work with the electric furnace. Dr. 



'Owing to delays in European mails, the report of Professor Kapteyn, given on page 255, could 

 not be refened to in this introductory sketch. 



