504 Trans. Acad. Sci. of St. Louis. 
that the average azimuth factor for the time stars is small, 
and the reversal of the instrument eliminates any small error 
in the adopted value of the collimation. 
All transits of stars were observed near the horizontal 
thread of the reticule and over all five of the vertical threads. 
The observed time used is the mean of the transits across 
the five threads. The time stars were observed on the 
chronograph and the circumpolar stars used for the deter- 
mination of azimuth were observed by eye and ear from the 
clock beats. A careful investigation shows no sensible differ- 
ence between the results of these two methods of observing. 
No incomplete transits were observed but I have nevertheless 
deduced from 12 eye and ear observations of circumpolar 
stars the following equatorial intervals of the threads of 
the reticule from the mean of the threads. The threads 
are lettered A, B,C, D, E, in order of transit of a star at 
upper culmination, Circle West, when the micrometer-head is 
turned toward the clamp. 
Hiquatorial Intervals from Mean of Threads of 2p5-inch 
Brunner Transit, October, 1891. 
— 68.252 + 08.007 
— 3.164 + 0 .007 
— 0 .070 + 0 .007 
+ 3.112 + 0.007 
+ 6 .372 + 0 .007 
AOA 
The inclination of the axis of the instrument was measured 
with the new striding level about 15 times each night. The 
levels for each night were plotted in a curve and the value of 
the level for each star was read off the curve. The adopted 
angular value of one division of this level as determined in 
October and November, 1891, by means of a level trier loaned 
by the Mississippi River Commission is — 
1 div. = 17.869 + 0.0045 = 08.125 + 0°.0003. 
The correction for inequality of the pivots of the instru- 
ment has been found to be 0°.000. 
The sidereal clock of the Observatory was used as the time- 
