(461) 



Dr. Myers, Prof. Ch. Andre ^), basing himself on different numerical 

 data, thinks himself justified in assuming, that the excentricity of the 

 orbit has increased since the time of Argelander, and also that the 

 major axis has been displaced. On this supposition Andre tries to 

 found an explanation of the terms of a higher order in the formula of 

 Argelander as corrected by Dr. Pannekoek ^). Finally Dr. L. Terkan 

 has brought forward some short considerations in A. N. n" 4067 ^). 

 Afterwards a more elaborate investigation has appeared in the Memoirs 

 of the Hungarian Academy of Sciences ''). 



We think that this enumeration covers the principal literature 

 about what has been put forward in explanation of the light- variation. 



2. The original plan of the author of the present paper was a 

 treatment by the method of Myers of the light curve derived by Dr. 

 Pannekoek, in order to ascertain whether any important change of 

 the elements of the orbits since the time of Argelander, might be 

 established. 



The first part of Myers' thesis in which, as a first approximation, 

 a circular orbit is derived, is generally fairly correct. But the second 

 part in w^hich this orbit is changed to a slightly excentric one, by 

 the aid of differential formulae, appeared to call urgently for a fresh 

 treatment. Erroneous normal equations have been derived from in- 

 correct differential formulae. The former have been wrongly solved 

 and finally the close adjustment of the theoretical curve to that of 

 Argelander, chiefly in the vicinity of the principal minimum, seems 

 to have been obtained by a ha])py coincidence of numerical errors. 

 It is of no use to enter into further particulars on the subject. As 

 an instance we give in the 2"^ column of the following table the 

 light-intensities {Ib), as derived by Myers from the observed grades 

 (Stufen) of Argelander during the period of from 30 hours before 

 to 30 hours after the principal minimum. In the next column are 

 contained the light-intensities {T(:\) given by Myers as resulting from 

 the definitive elements of his orbit ^), the 4^^ col. shows these same 

 quantities freed from numerical errors. In the three last columns the 



1) Traite d' Astronomie Stellaire par Gh. Andre, 2me p. NN. 460—1. 



2) Untersuchungen über den Lichtwechsel von (3 Lyrae. Dr. A. Pannekoek. Ver- 

 handelingen der Kon. Ak. van Wetensch. te Amsterdam, Vol. 5, N'. 7. id. A. N. 

 NO. 3456. 



3) Beitrag zur Berechnung dar Bahnelemente van (3 Lyrae. Dr L. TerkeIn. 



*) /3 Lyrae palyaelemeinek kiszamitasa spektroskopikai és photometriai adatokból. 

 Terkan Lajostól. — Mathematikai és Természettudomanyi Ertesitö, XXIV kötet 3 

 füzetéböl Budapest 1906. 



^) Inaugural-dissertation, p. 48 ; A. J. I.e. p. 16. 



