(18) 
on page 8 where in the columns A, the various values of Obs — 
Comp., as resulting from a comparison of the observations with 
System II, have been given already, these observations deviate in 
distance from 0”67 to 0"99 (in the same direction) from the com- 
puted ones, whereas the other distances, measured at Mt. Hamilton, 
fairly oscillate round them. The following consideration proves a 
priori that the latter must come nearer to the truth. The area of 
the sector traversed yearly is already known with great approxi- 
mation from the first part of the orbit. So in each new orbit 
‚rg are (9,—9O) must have about the same value as in the old one. 
Now 0,—0, is equal to 27°424 as appears from the normal posi- 
tions 19 and 21, and equal to 23°052 according to the old orbit. 
Half the difference of the logarithms is 9.96229 = log. 0.9168, so 
that the old distances must be diminished on an average by 8.32°/). 
This gives for 1897.0, 1898.0 and 1899.0 respectively 3"8, 4°0 
and 43 (compare the ephemeris below), whilst the observations at 
Lowell Observatory gave much greater values. 
The following table gives the yearly means obtained for a with 
their weights. It is easy to understand that from 1887 an error 
in 7 must appear magnified in a. 
1862 8"33 (14) 1873 738 (4) 1884 750 (74) 
1863 7.65 (2) 1874 7.63 (34) 1885 7.42 (4) 
1864 7.81 (2) 1875 7.49 (5) 1886 7.47 (5) 
1865 7.49 (23) 1876 7.75 (44) 1887 7.62 (3) 
1866 7.69 (64) 1877 7.64 (4) 1888 7.47 (2) 
1867 7.57 (3) 1878 7.66 (5) 1890 7.74 (1) 
1868 21.58 (44) |. 1879 HBL, (73) 1897) 7. BE 
1869 7.53 (43) 1880 7.49 (8) 1898 7.72 (3) 
L870", 7.69 (8) 1881 7.53 (104) 1899 7.85 (2) 
1871 7.65 (4) 1882 7.51 (8) 
1872 7.67 (54) 1888 7.62 (6) 
In tbe upper figure of the diagram accompanying this paper these 
values are laid down for the middle of the year and have been 
connected by right lines. One can see that the deviations are but 
