OF ARTS AND SCIENCKS. 



2G7 



liglii by about .'-H for grades 11 to 12 would reduce the residuals cor- 

 responding to r = 45°, 60°, 210°, 225°, 300°, and 315°. The residu- 

 als for v=:120° aud 135° would, however, be increased. The-e 

 changes are not to be recommended unless indicated by future photo- 

 metric measures of the comparison stars. 



■q Aijuike. AigeUiiider gave a light curve of this star in 1842, 

 Astron. ^^ueh., xix. 31)9, based upon 174 observations taken by him- 

 self and by Ileis. In 1857, he gave a second curve dependent on 411 

 of his own ob>ervations, Astron. Nach., xlv. 97. In Table VII. 

 the liglit of the comparison stars are given in grades and in logarithms, 

 according to Wolif. The cohimns have the same meaning as iu Table 

 V. As V Aquilce was not observed by M. "Wolff, it is unavoidably 

 excluded from the comparison. 



TABLE VII. — CoMPARisox Stars for -i] Aquil^. 



The first seven columns of Table VIII. have the same meaning as 

 in Table III. and give the values of v, of the time, of the light in 

 grades, in logarithms, and in percentages, a computed value, and the 

 residuals from this, or the fifth column minus the sixth. The compu- 

 tation is effected by the formula L = 73.6 -)- 20.0 sin {v — 60°) -|- 

 6.0 sin (2 y — 120°). The last four columns give the light iu grades, 

 logarithms, and percentages, and the residuals according to the second 

 curve of Argelander. The same theoretical formula is used in this 

 case, adding 1 so that the positive and negative residuals shall be 

 nearly equal. The light in this case, Z' = Z -[- 1 = 74.6 -|- 20.0 

 sin {v — 60°) + 6.0 sin (2w — 120°). 



8 Gephei. Argelander has given a light curve of this star in the 

 Astron. Nach., xix. 395. Curves are also given by Oudemans in the 

 paper cited above, and by Schbnfeld in Astron. Nach., Ixxv. 14. 

 The relation of grades to logarithms is given in Table IX., for Arge- 

 lander and Schonfeld. Oudemans has already reduced his scale to that 

 of Argelander. Unfortunately, Wolflf only measured those of the five 



