( 548 ) 
1150 ein. 7 1 2408568 
y= — 0. Sinan — 130.66 
From the terms of the yearly period follows a motion of the pole 
in an ellipse whose axes are 0."121 and 0."057; on September 28 
the pole is in the major axis, in the meridian 19° East of Greenwich. 
3. The following investigation intends to deduce the 14-monthly 
part of the motion of the pole from the results for the azimuth of 
the meridian marks of the Leiden observatory. The pier of the 
north mark was renewed in 1880, the pier of the south mark in 1882 ; 
the determinations of azimuth used for this research, were begun 
for the north mark only not until Juli 1882, for the mean azimuth 
of both marks in January 1884, and so in each case more than a 
year after the construction of the pier, when the masonry was for the 
greater part solidified. 
The period of the observations used here ends July 1896, and so 
includes 14 years or 12 14-monthly periods so that the variations 
of azimuth of the latter period could be deduced independently of 
the yearly period. The material consists of transits of « Ursae minoris 
in both culminations and without using the artificial horizon. The 
observers were E. F. v. D. SANDE BAKHUYZEN and J. H. WILTERDINK. 
The following tables I and II show, for both observers and cul- 
minations separately, the number of the observations made and their 
distribution over the years and the months. 
EAB aas 
July 1992 | 83 | sa | 85 | so | 97 | 88 | so | 90 | 02 | 92 | 98 94 | 95 
Ek aay beke ide 95 | 96 
Observer: E. F. v. D. 8. BAKHUYZEN, 
25 | an 
| 
18 | 13 | 16 
| 6 
as | 14 | 9 | 5 
Bee 
9 | 94 12 | 95 
| | 
Observer: J. H. WILTERDINK. 
10 
1s | 93 | 90 
ze far [an or | 
| 
| 
