190 REPORTS ON INVESTIGATIONS AND PROJECTS. 



of these results is the discovery of the largest apparently constant radial ve- 

 locity so far observed. It is that of the star Lalande 15290, 7^ 48™, mag. 

 8.2, and amounts to -248 km. per second. 



The discovery by Enebo on March 13, 1912, of a new star in Gemini af- 

 forded a favorable opportunity for a series of observations upon one of these 

 important and remarkable objects. The star was observed as regularly as 

 possible from March 22 until May 27, when it reached too great a western 

 hour-angle for further observation. During this interval the brightness of 

 the star decreased from 5.0 to 8.5. 



The principal results of a study of the spectrograms are as follows : 

 (i) The changes in the character of the spectrum are similar to those 

 found in the case of Nova Persei and other new stars, the decrease in bright- 

 ness being accompanied by the disappearance of the dark lines, a weakening 

 of the continuous spectrum, and a gradual approach of the spectrum to that 

 found to be characteristic of planetary nebulae. 



(2) The radial velocity of the star is probably constant and about -j-io 

 km. per second. 



(3) The displacements of the dark and the bright hydrogen bands, and 

 their widths, appear to be closely proportional to wave-length, a result found 

 by Campbell and Wright for Nova Persei. 



(4) A marked similarity appears to exist between the spectrum of the 

 Nova and that of certain Wolf-Rayet stars, both as regards the bands pres- 

 ent and their relative widths. 



(5) Our observations show no marked evidence of the presence of the 

 spectrum of radium or of the radium emanation in the Nova spectrum. 



(6) There appears to be considerable evidence for the presence of the 

 nitrogen spark spectrum in the Nova, an identification suggested by Wright 

 in the case of Nova Lacertce. 



(7) There is no evidence of circular polarization in the complex bright 

 bands of the Nova spectrum. 



Classification of Stellar Spectra. 



During the year Mr. Kohlschiitter has carried on the classification of the 

 spectra of the stars photographed with the Cassegrain spectrograph. The 

 system used was that of the Harvard Observatory, in which six types are 

 distinguished, B, A, F, G, K, and M. By far the greater part of the spectra 

 investigated belong to types A and B, although a considerable number of 

 spectrograms of stars with known parallaxes, which belong to types F to M, 

 have been examined as well. 



The linear scale of the spectrograms is considerably greater than that 

 usually employed for classification purposes. As a consequence a smaller 

 extent of spectrum can be used than in the case of the lower dispersion 

 photographs, and some lines, notably H and K, can not be employed as 

 criteria for classification. On the other hand, the finer lines are much better 



