( 547 ) 
from its mean place in the direction of the meridian of Greenwich (c) 
and in the direction of 90° West of Greenwich (y), then we can repre- 
sent the azimuthal deviation A of a meridian with regard to its mean 
direction for a place at geographical longitude 4 (West of Greenwich) 
and latitude (2, in seconds of time by the formula: 
+ (a sin À — y cos À) ei EN 
This formula represents also the variable part of each azimuth 
when these azimuths are taken so as to inerease from North to West. 
2. Prof. Tu. ALBRECHT?) has deduced from the variations of latitude 
of several places a continuous series of values for the co-ordinates 
« and y, beginning with 1890.0 ; these show that the path of the pole of 
the earth is geometrically rather intricate. In 1891 Dr.S. C. CHANDLER 
found a 14-monthly as well as a yearly period in the motion of the 
pole, but thought that two periodical terms of the periods mentioned 
would be insufficient to express the co-ordinates of this motion. 
Dr. E. F. v. D. SANDE BAKHUYZEN on the contrary has contented 
himself with using these two periodical terms *). According to his 
computation the results derived with regard to the motion of the pole 
from observations after 1858 can be brought to agree fairly well with the 
supposition that each of the co-ordinates # and y consists of 2 singly- 
periodical terms one having a period of about 14 months, the other 
of exactly a year. It appears then that the terms of the 14-monthly 
period may also be the components of a circular motion of the pole. 
The most probable elements of this circular motion are according 
to Dr. B. F. v. D. SANDE BAKHUYZEN: 
Period 430.66 days 
Amplitude 0.”159 
Epoch of the greatest latitude / Julian date 2408568 
for Greenwich j or 1882 May 2 
and the components for the Julian date ¢ corresponding to this: 
t — 2408568 
== + 0."159 cos. 2 
re ee 
') Tu. Auprecut, Berichte über den Stand der Erforschung der Breitenvariation, 
in December 1897, 98, und 99, 
*) B, FP. van DE Saype BAKHUYZEN, Sur le mouvement du pôle terrestre, d'après 
les observations des années 1890—97, et les résultats des observations antérieures. 
Archiv, Néerl. Série 2. LT. II, 
