224 A. Hall— Variations of Latitude. 
observations with better tables of refraction, have caused the 
disappearance of nearly all the anomalies that formerly ap- 
t @ priori would not perhaps seem probable. Thus we 
might have geological changes that would alter the position of 
the vertical line at a station; or again, such as would cause a 
radual or secular change in the position of the earth’s axis of 
rotation, by shifting large masses of matter on the earth’s sur- 
ace or in its interior, and these changes might produce varia 
tions of latitude. In fact it is for the purpose of testing local 
changes that Mr. Fergola has chosen stations which have 4 
large difference of longitude. The table of latitudes publisbed 
some years ago by this astronomer does seem to show a seculal 
change in the latitudes of northern observatories. This table's 
as follows: 
Place. Date. Latitude. 
Washington -. _---- 1845 + 38° 53’ 39°25 
Washington -_..--- 1863 38 °78 
BOE, cas one 1825 48° 50’ 1370 
Paris 1853 ito 
Milan. eee sou ck 1811 45° 27' 60"°7 
RR oe cis ei ASTI 59 “19 
Rome 1810 41° 53’ 54”'26 
MOM. woman ecss < 1866 54 °09 
Naplew <= 305 1820 40° 51’ 467°63 
Naepiee Saco oso. 1871 45 “41 
Konigsberg __-___--- 1820 54° 42’ 50"°71 
Konigsberg__...__- 1843 50 “56 
Greenwich _______- 1838 4 51° 28’ 387°43 
Greenwich _....__. 1845 38 17 
Greenwich ____._.. 1856 37 °92 
It will be seen here that without a single exception the pes 
tudes given in the table have diminished during the grein 
intervals of time so many changes have occurred in 
ments and among the astronomers that the diminution of ar 
tude may be only apparent. The most complete investig® we 
of this question is that by Mr. Nyrén of the Pulkowa sai tb 
atory. In this case the observations have all been : 
on of 
D 
accuracy. The probable error of a single determinatio Pal: 
ae is only + 0-2. The results for the latitude of °” 
wa are: 
