STUDIES IN STELLAR STATISTICS, II. 21 
Class B. 
Typical star y Orionis, and « Lupi. 
These spectra differ from .that of 3 Gentauri of Class Bı principally in the greater 
intensity of the lines due to helium, in the diminished intensity of lines 4089.» and 4649.2, 
and in the absence of line 4116.2. 
The lines due to helium appear to reach their maximum intensity in spectra of this 
class. Those having the greatest intensities are at wave lengths 3819.2, 4009.5, 4026.4, 
4144.0, 4387.8, 4471.8, and 4922.1, all of which belong to the first subordinate series of 
(either) helium (or parhelium). 
The characteristic lines of spectra of Classes Bo and B: which are not due to helium 
are faint. 4089.2 and 4649.2 are about 0.5 as intense as in Clsss Bı, and 4116.» is not 
seen. Among the fainter lines, 4267.4 and 4481.4 are noticeable. The line, K, is 2.0 as 
intense as in Class B1. 
Class bs. 
Typical star, @ Pavonis. 
A marked diminution in the number of Orion lines is noticed. Almost all of the 
fainter lines of the spectra of Class P2 have disappeared, and on plates taken with one prism, 
few dark lines are seen, except those due to hydrogen or helium. 
The helium lines, while of about the same intensity as in spectra of Class B2, are 
more prominent in this spectrum, on account of the faintness, or absence of many other 
lines. 46492 is extremely faint, and is not seen on plates taken with one prism. 4089.2 
is not present. 4128.5, 4131.4, and 4481.4 are more intense than in spectra of Class 
Bz. 3926.8 is more intense than the line A. 
Class Bs. 
Typical star,  Velorum. 
The spectrum shows a decided advance towards spectra of Class A, in the increased 
intensity of the four lines, K, 41285, 4131.4, and 4481.4. 
The lines of hydrogen are 0.6 as intense as in @ Canis Majoris. 
The lines of helium are the same as in spectra of Class P3, but they are less intense. 
Almost all the fainter lines characteristic of the spectra of classes Bo, B1, and Ba, 
are absent. It is interesting to note that, of the three intense lines 4089.2, 4116.2, and 4649.2, 
characteristic of Class Bo, 4116.2 disappears in Class B2, 4089.2 in Class Bs, and 4649.2 
in Class B5. "They all become very faint in the class preceding the one in which they are 
invisible. 
For each one of these subclasses I have determined the value 
of À and M, considering separately all stars brighter than the 5‘ 
magnitude, those brighter than the 6” but fainter than the 5" magni- 
tude, and finally all stars brighter than the 6" magnitude. 
