147 



Before investigating this we mnst note another circumstance. F'or 

 the years 1905 — 1909 the observations of Mösting A in right-ascen- 

 sion were also used and it is impossible to say what influence tliis 

 has had. Observations of the limbs and of tlie crater are intermixed 

 in each of the 20 equations deduced from each year's observations 

 and cannot be easily separated. 



I have, therefore, made a new calculation of the empirical term 

 and simply left out the six last years. Of the seven normal [)laces 

 (de Vos p. 139) I have left out the last and I took for the last 

 but one the mean results of only 4 years 1901 — 1904. A new solu- 

 tion then gave 



X = 253°.7 + 40°.67 (^—1900.0) 



and we thus find an annual variation exactly equal to tlie annual 

 motion of the perigee. 



A new calculation of the co-efïïcient then gave (calculation B sec 

 DE Vos p. 139) 



/5 = — 0".44 li' = + 0".67 



Y= i- 0".66 r' = + 0".26 



from which follows for the co-efTicient itself « = -|- 0".75, a value 

 even greater than before. As argument for 1900.0 we now get 

 Xo = 251°.6, thus as the mean from the two calculations 252°. 7, and 

 the term becomes 



-h 0".75 sin i252°.7 + 40°.67 (/— 1900.0)| 



= .4_0".75 5m(/— 81°.6) 



now deviating slightly more from the form — « cos I. 



The empirical term was now again subtracted from the —ho and 

 — k^: I with the co-efficient 0".75 found here, II with the co-efficient 

 0".40. Calculating in both cases the mean discordance we found. 



From these results it is clear in the tirst place, that for tlie 

 period since 1890 the mean residual discordance is distinctly smaller 

 than before, so that the results from the observations of the limbs and 

 from those of the crater appear not to make a completely homogeneous 

 whole. De Vos himself had already observed that exactly- the last 

 years, since the crater-observations were added, gave less regular 



10* 



