The Motion and Distribution of the Sun-spots 53 



from 1874 — 1911, published in the Greenv^^ich Observations, Dyson and 

 Maunder, as stated on page 1 1, have computed the following corrections of these values: 



J AI= — 4'.4; 



\^L sin/= + 1'.7 . 



Even if these corrections should in no wise be considered definite, the paper 

 by Dyson and Maunder just mentioned is of some interest, since it clearly 

 proves that the position of the rotation axis 

 can only be determined with considerable 

 inaccuracy. 



It is easily seen that if the axis is 

 erroneously determined, this will cause an 

 annual period in the latitude motions of the 

 spots. Now Dyson and Maunder have not 

 found any such period in their material of 

 observation. Hence it seems as if we should 

 be in a position to infer that the inclination 

 did not require any sensible correction. 

 Their following treatment of the latitude 

 motions gives, nevertheless, as the result 

 the above values. 



These values of A/ and sin 1 are 

 averages of values computed for each year. 

 About the sun-spot minima three years are 

 usually taken together. In every such group 

 the number of observations varies between 

 50 and 150 or there abouts. In computing 

 the final averages the years 1874 — 77 have 

 been omitted, during which time the observa- 

 tions give the values A/= + 12'. 4 and 

 AL sin /= — 9'. 8, which considerably differ 

 from the mean. The authors have not 

 calculated any mean errors. If we compute 

 the mean errors of the results from the 23 groups, in which the material is divided, 

 we obtain, without considering the weights, 



A/= — 4'.6 ± 1'.2 

 ALsin /= + 1'.6 ± 1'.3 



Hence it follows that one can hardly attach any importance at least to the 

 correction of L. As regards the correction of / it varies in such a degree that it 

 seems impossible from the motions of the spots to determine the position of the 

 sun's axis more accurately than has hitherto been done. This appears most clearly 



TABLE XXV. 

 Values of ALsin J and A/ according to 

 Dyson and Maunder. 



Period 



Weight 



ALsin I 



A7 



1874—1877 



282 



- 9.8 



+ \2A 



1880 





1 







304 



-j- <i.4 



9 2 



1882 



345 



-f 9.1 



— 



1883 



448 



- Ü.2 



- 48 



1884 



460 



-fll.7 



— 05 



1885 



879 



-fll.5 



— 4.5 



1886-1888 



339 



— 1.8 



- 8.1 



1889—1891 



355 



— 3.9 



- 4.2 



1892 



541 



+ 6.1 



— 9.4 



1893 



694 



+ 16 



— 8.6 



1894 



644 



+ 3.1 



-f 0.4 



1895 



497 



+ 5.7 



- 9.7 



1896 



251 



- 4.2 



-11.8 



1897 



221 



+ 8.2 



— 12.8 



1898—1900 



311 



— 4.3 



— 18.5 



1901—1908 



203 



+ 53 



- 1.4 



1904 



288 



+ 1.8 



+ 5.6 



1905 



220 



+ 8.7 



— 6.5 



1906 



407 



— 5.1 



— 2.9 



1907 



473 



+ 0.9 



+ 8.3 



1908 



372 



- 6.9 



— 4.0 



1909 



369 



— 9.7 



-f 2.0 



1910-1911 



217 



- 3.7 



+ 3.2 



1878- 1888 



2484 



+ 5.3 



- 5.7 



1889-1900 



3535 



+ 2.1 



— 7.7 



1901-1911 



2552 



- 2.0 



-f 1.8 



1878-1911 



8546 



+ 1-7 



— 4.4 



