( 472 ) 



from the same distance, but from a larger field, are united to a 

 larger disc" ^), seems little satisfactory. 



10. Determination of the elements of the orbit etc. by means of 

 the light-curve of Argelander ^). 



As a first approximation we put i = 90^ e =^ 0. 



Ah approximate value of q is furnished by the general course of 

 the curve in the vicinity of the maxima. As long as it is symmetrical 

 in regard to the ordinate of the maximum, we may assume that the 

 eclipse has not yet begun, so that 



J = [/{I — s' siji" ntju ) ; 

 tM being the time counted from the maximum. 



From the light-curve we take the decrease of {Oo — ^) ^^ grades, 

 for equal intervals of time before and after the two maxima. 



—30 

 — 2i 



— 18 

 —12 



— 6 

 + 6 

 +12 

 +18 

 +24 

 -f-30 



h 



^. K-Ö). 



± 6' 



±12 

 +18 



0.025 

 0.093 

 220 



hi 

 —\S' 

 -12 

 — 6 

 + 6 

 +12 

 +18 



{0-C)^{0-C) 



11 



An increasing dissymmetry begins to show itself for both the 

 maxima at about 24 hours distance from these epochs. 



With the mean values {o^ — o)inean the light-intensities were now 

 computed by the formula: 



log J 



(J„ — 6 = 



0.13 



and the relation 



8" Si7l^ 7ltM = 1 — J' 



M 3 Lyrae palyaelemeinek etc. p. 417. 



•) De Stella 3 Lyrae vnriabili commentatio altera. ScripsitFREDERicus Argelander 

 Bonnae a. 1859. — Curva ""vera" pro 1850. 



