The Laws Observatory. 501 
its on six nights give twelve independent determinations of 
the latitude which are arranged in the following table. 
SUMMARY OF RESULTS OF LATITUDE FROM PRIME VERTICAL TRANSITS. 
g s 
Star. 3 a. g, and ¢.. minus 9 
n* 
* Herculis... S| omy tT | ee oe ees | kt".68 | eee" Oo On"06 
@Herculis..) 5S | (17 oy ee 53.23 
“ 17 57 .47 
ore W]e sean visite 
“17 54 .99 
6 Lyrae..... . “ 15 47 ‘81 se 51 .40 
m Herculis.:| S| oe an oy | 6 a8 51 .44 
6 Herculis.. . Mn pd a 6 .85 52 .02 
tc 693 B4 » 
a Lyrae..... oer 47 56 6 .78 50 .95 
“ 93 54 4 
6 Lyrae..... “a 48 (10 6 .36 51 .28 
= Herculis.. N . Po “9 i 6 .15 51 .62 
@Herculis... 8 | 4, 35 vag el By Sy 52 .34 
Feo 25 55 .79 9 52 .22 
a Lyrae.,... N . 99 48 66 4.2 
I. 54 .81 9 | +38 56 52 .02 
Gey! | ee 99 | 498 66 49 22 | + Ceeegeemas 
oe ee ee 
In combining these results for the final value of the latitude 
for this epoch, the mean results for each of the four stars 
have been given the same weight, or what is the same thing, 
the simple mean of the twelve determinations is adopted, and 
we have — 
g = + 38° 56’ 51”.923 + 0”.121 on July 22d, 1891. 
REDUCTION TO MEAN LATITUDE. 
Since the fact of variation of latitudes periodically by a 
sensible amount seems to have been established beyond rea- 
sonable doubt, it remains to reduce the above determinations 
of latitude to the mean value for this place. Any minute 
secular change of latitudes which may exist is so small that 
