MOUNT WILSON SOLAR OBSERVATORY. 291 



(52) The radial velocity increases rapidly with the proper motion 

 for the F, G, K, and M stars, and probably for the A and B stars as well. 

 A satisfactory explanation of the change has been found. 



(53) The stars of very low absolute luminosity and, probably of 

 small mass, have exceptionally high radial velocities. 



(54) Twenty-one spectroscopic binaries have been found during the 

 year, 6 of which show the presence of two spectra on the photographs. 



(55) Four stars show radial velocities of +114, +290, —148, and 

 — 179 km., respectively. 



(56) Twenty stars in the h and x Persei clusters show a common 

 radial velocity of —40 km. The average spectrum of these stars is 

 B 6, and their magnitudes range from 6.3 to 8.6. 



(57) The radial velocity of the Andromeda nebula has been measured 

 as -329 km.; and of the bright-line nebula N. G. C. 1068 as +765 km. 



(58) Observations of the spectra of bright and faint stars in the 

 Hyades, and of pairs of small proper-motion stars, tend to indicate 

 that the fainter stars intrinsically have spectra which are relatively 

 more intense in the violet portion of the continuous specti-um. 



(59) The method of determining the absolute magnitudes of stars, 

 and hence their individual parallaxes, from the relative intensities of 

 certain Unes in their spectra has been continued with success through- 

 out the year. A considerable gain in accuracy is to be expected from 

 a revision of the standards of reference for the more distant stars based 

 on parallax observations now in progress. 



(60) During the year the spectrum of Nova Geminorum of 1912 

 has passed from one resembling a planetary nebula into that of a 

 Wolf-Rayet star. 



(61) The irregular variable star T Tauri is surrounded by an exten- 

 sive atmosphere about 4" in diameter, which shows the bright Unes 

 characteristic of Wolf-Rayet spectra. The spectrum of the star proper 

 is about F 5. 



(62) The spectra of stars of very low intrinsic brightness show types 

 ranging from K5 to Mb. An exception, however, is the companion 

 to 0^ Eridani, which has the spectmm A 0. 



(63) The spectra of 18 stars in the cluster Messier 15 range in type 

 from A 5 to F 5, with one star about GO. 



(64) 840 cobalt and 423 nickel lines in the range X3000-X7100 have 

 been classified in the electric-furnace spectrum with regard to their 

 initial appearance and changes with temperature. 



(65) The tube-arc has been found to produce line-dissymmetries 

 varjdng greatly in magnitude, these being in general toward the red, 

 but in some cases toward the violet. They have been studied with 

 reference to their bearing on changes of wave-length, measurements of 

 the displacements being made with the microphotometer, and have 

 been found to be related to the furnace classification of the lines. 



