218 CARNEGIE INSTITUTION OF W.\SHINGTON. 



(4) The radial velocities of 95 stars with measured parallaxes have 

 been obtained. These stars all have large proper motions and are 

 for the most part of the spectral types F to M. 

 Their magnitudes range from 5.5 to 8.2. The abso- 

 lute motions in space for 61 of these stars have 

 been calculated, and although the resulting veloci- 

 ties are, of course, much affected by the errors in the 

 determinations of the parallaxes, it may be of interest 

 to note the result shown in the accompanying table. 



A velocity of 590 km. is found for the star Lacaille 8381, but it 

 seems nrobable that the measured parallax of this star is too small. 



(5) Observations of a number of stars in the h and X Persei 

 clusters show that a considerable number of these stars are moving 

 with the same radial velocity and in all probability form a group. 

 Of a total of 14 stars observed, 9 have the same radial velocity 

 within the limits of errors of measurement. Their spectra are all 

 of types B and A. Of the stars which do not belong to the group, 

 three are of types F to K and the other two lie at a considerable 

 distance from the mean positions of the stars forming the group. 

 The average velocity of the nine stars is —43 km., an exceptionally 

 high value for stars having this type of spectrum. 



NOVA GEMINORUM NO. 2. 



Observations of the spectrum of Nova Geminorum No. 2 during 

 the year have led to the following conclusions : 



(a) The bright bands show the presence of marked absorption on 

 the latest photographs taken in April 1913. This is over 13 months 

 after the discovery of the Nova. All of the bright bands have the 

 same characteristics of structure. 



(6) There have been no marked changes in the widths or the dis- 

 placements of the bright bands since they became a prominent feature 

 of the star's spectrum. The average displacement of the principal 

 bands on the negative of April 1913 was about 1.0 a toward the red. 



(c) The hj^drogen band at X4686 has shown some remarkable 

 fluctuations in intensity. A sudden change in the brightness of the 

 star between November 15 and 17, 1912, observed by Professor 

 Barnard, is probably due mainly to the variation of this line. In 

 view of Professor Fowler's recent discovery of this line in the labora- 

 tory and his observations of its variations with differences in the 

 relative amounts of hydrogen and helium present in a mixture, the 

 variations of this line in the Nova spectrum are of peculiar interest. 



COMPANION OF RIGEL, 



Observations of the spectrum of the companion of Rigel (fi Ononis), 

 magnitude about 6.8, show that this faint star has a spectrum nearly 

 identical with that of the principal star, which is about seven mag- 



