L. C. Pickering—Light of Comparison Stars for Vesta. 19 | 
- column and are therefore partly attributable to errors of obser- 
vation. In the seventh line from the end of Professor Harring- 
ton’s table, 5°84 is assumed to be a misprint for 6°84. 
Sidereal time of 
Observation. Magn. Residuals. 
April, 1883. of Vesta. Vesta. Stars. . 
d. h. m. 
0 1 Meets 1 | 7-2) +°57 —'24 
Tos RI SE 6°59 —°05 +°05 
TV GT 617 —47 —'26 
EV ee §°39 —'25 —'19 
kD; aL; SB 6°55 —'09 +:°02 
SL 319 6:43 —21 +°07 
3 6°32 —"32 —'14 
16 x 3 6°73 +°09 
Sto 66 6°85 +°21 +°03 
XIt, 26 6°43 —'l +:°14 
xm «65 6°78 +°14 +11 
xin 2.24 6°69 +°05 —14 
XE 49 6°19 +°15 —'12 
atv. 18 6°79 +°15 +°05 
hrs 38 6°52 -'l +09 
py | 6°47 —17 +12 
‘ x. 40 6°48 —'16 +'1l 
xt 5 6°75 +-1l — 03 
mi 39 6°51 —'13 *+°12 
xi «€660 6°52 —'12 +°14 
6 o Soaeriat 13 6°61 —'03 +°02 
ai: 3} 6°62 —'02 —°22 
1930 at 6°67 +°03 —_ 
yt Rare 2 | 8 6°82 +°18 +°07 
x11 «#658 6°85 +°21 +°17 
S00. Bk 0 6°91 +°27 —'02 
ae ose SE 6°84 +°20 +°03 
6°64 4°17 +:'10 
The mean result for the magnitude of Vesta, 6°64, may be 
compared with the results formerly obtained at this Observatory 
and published in the Astronomische Nachrichten, cii, 151. The 
value obtained from observations on 12 nights in 1880 was 6°49, 
and from observations on 10 nights in 1881-2 was 6-45. The 
differences between these values and that derived from Professor 
ington’s observations do not seem large, considering the 
fact that the two methods of observation were very dissimilar. 
In measuring large intervals of brightness with the wedge pho- 
tometer systematic errors may perhaps result from irregularities 
in the tint of the glass and other causes. On the other hand, 
the small meridian photometer used in the observations of 
Vesta was not designed for measuring the light of objects fainter 
than the sixth magnitude, and even the brightest asteroids were 
seen in the instrument with some little difficulty. 
The magnitude 6°51 found for Vesta in vol. xi of the Annals 
of this Observatory, page 294, was obtained by an indirect pro- __ 
cess, and its close agreement with the later results just mentioned _ 
1s probably accidental. ka’ oe 
College Observatory, Cambridge, Mass., May 19, 1884. 
