( 462 ) 



same quantities have been given reduced to light-grades (o). I do 

 not find mentioned wiiat is the vahie of a light-grade of Argelander 

 according to Myers. From the light-intensities in the two minima I 

 find 0.130 magnitudes, a value to which I have adhered. The intensity 

 of the maximum has been taken for unit. The light-grades of A 

 which, from 3.35 in the principal minimum, rise to the value 12.35 

 at a maximum, have been reduced to the interval of 3.00 to 12.00 

 for the sake of convenience. 



In what follows we have tried, first of all, to give correct formulae 

 for the derivation of a slightly excentric orbit from the variation of 

 the light. These have then been used for the curve of Argelander 

 and for that of Dr. Pannekoek. Afterwards the spectroscopic data 

 of Belopolsky have also been freshly reduced, because there is some 

 uncertainty about the resulting orbit ^). This is perhaps to be attri- 

 buted to the method of Lehman — Filhes^). This method is excellent 

 for a satisfactory determination of the excentricity if it is large; but 

 it is less suitable for a very small excentricity. For the drawing of 

 the graphical velocity -curve remains always slightly arbitrary and 

 this fact exerts too strong an influence in the case that e is small. 



3. We thus start from the following hypothesis : 



1) In the "Recherches nouvelles" (Memorie etc.) Belopolsky gives e = 0.04; in 

 his "New investigations" (A. J.) e = 0.07, as the result of the same observations. 



2) A. N. n. 3242. 



