STELLAR PHOTOGRAPHY. 



213 



of Pritchard, Monthly Notices Royal Astron. Soc, XLIL, p. 227; c, observations in 

 Uranometria Oxoniensis, p. 94 ; and d, observations in Harvard Observatory Annals, 

 XIV., p. 398. To correct for the difference in the zero of the scale of these four 

 catalogues, their magnitudes were first corrected by adding the quantities — 0.07, 

 —0.15, —0.12, and +0.10, respectively, before subtracting the photographic magni- 

 tudes. The sums of the positive and negative residuals for each catalogue were 

 thus made nearly equal. The last column describes the spectrum. A denotes that 

 the character of the spectrum is uncertain, owing to the presence of an adjacent 

 star ; F, that the spectrum is too faint to render its character certain , I, that the 

 spectrum belongs to Class I. as described above ; R, that the spectrum possesses 

 some peculiarity more fully explained in the remarks following the table. These 

 remarks also indicate which stars interfere when A is entered in the last column, 

 and give additional observations when the first measures are discordant. 



TABLE IV. 



