STUDIES IN STELLAR STATISTICS. ll. 53 
putations, since it has been found by GYLLENBERG that the value of 
the parameter R for stars of the subclass Oe 5 B — accidentally — 
does not materially deviate from the value of this parameter charac- 
terizing stars of the subclass Bs. From this reason I have not found 
it necessary to make a new computation with those stars excluded. 
When I had already finished the computations reported in the 
preceding paragraphs I found that the Catalogue of PrckERING in H. A. 
56 does not contain all stars of type B recorded in the Annals of the 
Harvard observatory. Comparing my catalogue with »The revised 
Harvard Photometry catalogue» in H. A. 50. I found 54 stars of the 
spectral type B which were not registered in H. A. 56'. Consequently 
I have eomputed the coordinates of these 54 stars and have inserted 
them into the catalogue, which is thus brought up to 805 numbers, 
including the ten stars of the subclass Oe 5 B, which properly had to 
be excluded. 
I have not eonsidered it necessary to recapitulate the computa- 
tion of the direction of the principal axes of the Galaxy, taking into 
account the 54 stars not included in H. A. 56, nor have I corrected 
the coordinates of the centre for these stars, though such a correc- 
tion could be easily made. The diagrams on plates III—V show that 
the orientation of the axes cannot be materially in error and I think 
it is imprudent to make successive corrections to the galactie system 
of axes defined above, which may be used to advantage till the stars 
of the spectral type 4 are as completely known as now the stars of 
the spectral type B. A new determination of the principal axes of 
the Galaxy ean then be performed with considerable accuracy’. 
1 [t is to be regretted that the memoirs in the Harvard Annals are not separately 
dated. The preface to H. A. 56 is dated oct. 1912, and that to H. A. 50 March 1908, 
but evidently the memoir on the B-stars in H. A. 56 is written before the completion of 
H. A. 50. 
? | learn from a letter of M:r Pickerine, dated March 21, 1912, that Miss Cannon 
is at work on the revised Draper Catalogue, which will give the class of spectrum of about 
100000 stars. I suppose that the greater part of the A-stars will be found in this catalogue. 
(During the print of this memoir I gather from another letter of M. Pickerine that the classi- 
fication of the spectra is now practically completed. Miss Cannon has classified the spectra 
of about 290000 stars. "The work will fill eight volumes of the Annals, of which the first 
one is nearly completed. A special catalogue af all B stars is also planned). 
