The Laws Observatory. 499 
with the striding level indicate that the pivots are sensibly 
equal in diameter and show no evidence of irregularity in 
their form. But all possible error arising from inequality 
in the diameters of the pivots has been eliminated by the 
reversal of the instrument. The collimation was reduced by 
adjustment to less than half a second of time before work was 
commenced and it remained very nearly constant during the 
entire series of observations. The instrument was never 
reversed during a night’s work. The circle was south on July 
17, 23 and 25, and north on July 15, 24 and 29. 
As there were no means of determining the clock 4T on 
each night while the prime vertical observations were being 
made I determined to observe only those stars which could be 
conveniently observed at both east and west transit. The four 
Berliner Jahrbuch stars, x Herculis, @ Herculis, a Lyrae and 
§ Lyrae were selected for this purpose. This determination 
of the latitude depends on the declinations of these four 
stars. They were all observed with the Repsold meridian 
circle of the Washburn Observatory during the years 1888-9, 
and the corrections given below have been taken from Vol. 
VIII of the Publications of that Observatory. These declina- 
tions were deduced from the nadir point of the instrument and 
have not been reduced to the declination system of the Berliner 
Jahrbuch. The corrections to the B. J. declinations indicated 
are given below. They confirm in a general way the accuracy 
of the B. J. declinations. The apparent declinations of these 
stars as given in the B. J. for 1891 have been adopted. 
x Herculis + 0’.62 4 
6 Herculis +0 .03 9 
a Lyrae ww () 20 6 
6 Lyrae +0 46 12 
The Observations were Reduced by a slight modification of the 
method of Professor Benjamin Pierce as presented in Chau- 
venet’s Spherical and Practical Astronomy, Vol. Il, p. 255. 
By this method the observations of the different nights are 
reduced in pairs, the circle having been south on one night 
