220 



STELLAR PnOTOGRAPIIY. 



the star. The result, which is given in the fourth column, shows the actual photo- 

 graphic brightness of these stars. The fifth column gives the Durchmusterung mag- 

 nitude, and the final column gives the residual found by subtracting the photographic 

 from the DM. magnitudes, after reducing the scale of the latter to that of the former. 

 Positive residuals indicate stars of a bluish color, and negative residuals those of a 

 reddish color, provided no errors are present. 



No. 5, or DM. +89' 5, is shown to consist of two equal stars, whose combined 

 light would equal that of a star of the magnitude lO.G, and give a residual zero in 

 the last column. Nos. 14 and 15 are so neai'lj in the same declination that their 

 trails coalesce, although separate at the ends. Their combined light was originally 

 measured, and the measures given were made subsequently. No. 27 was originally 

 omitted, since by precession it is now outside of the limit of one degree north polar 

 distance. 



The greater portion of the stars in Table VI. differ but little in brightness. 

 Accordingly, measurements were made of the polar stars proposed as standards of 



TABLE VII. 



