made by Reichenbach for the Observatory at Konigsberg. 47 
the influence of temperature on the adjustments of the instru- 
ments. In my “ Treatise on the Fundamental Catalogue,” I 
have given data which confirm the correctness of my former de- 
terminations ; yet the opportunity for a new trial, which the 
particular excellence of the new erection (aufstellung) and the 
admirable regularity of Repsold’s clock offered to me, were par- 
ticularly favourable for this purpose. 1 therefore reduced the 
25 observations that have as yet occurred, and find for 1820 as 
follows : 
1820. H: M. S. 1821. H. M. 8. 
March 22 = 7.29.52,70 February 8 = 7.29.52,49 
June 23 3 37 "9 ue 69 
July 28 x: 37 11 fs 54 
30 a 44 13 a ites | 
August 5 a 2 27 uit 32 
8 ee 44 March 23 es 45 
29 as 62 _ 24 ey 64 
September 8 te 47 25 Ke 63 
9 Os 40) 26 ae 50 
11 a6 44 29 os 56 
13 as 37 30 ee 59 
15 a, 32 31 - 33 
December30 es 38 
The mean is 7" 29’ 52”,494, or only 0’,033 greater than my 
determination for 1815. So that the correctness of the former 
determination is hereby confirmed. I also believe that the me- 
thod employed by Mr. Pond will not protect him from a con- 
stant error in opposite groups of stars. By his method a star 
is reduced with the mean of all that have been observed on the 
same day, according to the data in Dr. Maskelyne’s catalogue ; 
and the new catalogue thence arising is settled with reference to 
the equinoxes. This method would be strictly correct, if the 
36 stars were all observed in one day; but as there will be many 
more days, where the stars in one quarter of the heavens are 
observed alone, than where they are observed at the same time 
with those opposite thereto, it is evident that an error arising in 
such quarter can only disappear in part; and the less so the 
more frequently the stars are observed in such particular quarter : 
since thereby the error obtains a greater preponderance. As 
Mr. Pond’s determinations are founded on 151 observations with 
a celebrated instrument, and by so celebrated an astronomer, 
and as my determinations too have received undeniable confir- 
mation ; I can see only this mode. of accounting tor the discord- 
ancies, 
The 
