SECULAR (.HANCK I X THK PERIOD OF U CARIN.E. 1 57 



epoch of first maxinmni in 1900: column 3 _ii;^ives the numher 

 of maxima used to obtain the mean period for the year ; column 

 4 gives the mean observed maxima for any one year, all the 

 observations of the year being combined to obtain this mean ; 

 column 5 gives coiujjuted maxima from the elements. 



2415032.60+ (38d.765)E: 

 and column 6 gives the residuals (O-C). 



The remaining two columns. 7 and 8. will be referred to 

 later. 



If now the residuals ( ( )-C), set forth in column 6 be plotted 

 down, the secular and circular character of their departure from 

 the mean will be at once evident. It will appear that the cycle 

 is completed in 180 periods, or 6978 days, the amplitude of 

 variation being 0.65 days. 



We have, therefore, as a new determination of the elements 

 ■of L^ Carinas, the following : — 



Max = 2415032.68 + 38.7647E 



+ o^'.65 cos (212° — 2° E). 

 The computed maxima determined from these elements are given 

 in column 7 and the corresponding residuals in column 8. 



If we compare the values in columns 6 and 8, the nearness 

 w^ith which the final elements given above are an interpretation 

 of the light changes of the star will be manifest. 



The interpretation, put in words, is this : The star U Carinae 

 varies in a mean period of 38.7647 days. But this period is 

 constantly changing between the limits 



38.73 days and 38.79 days, 

 all the changes being completed in 180 periods, 

 or 6978 days. 



