( 549 ) 
TA Bi ie ff. 
Months. | J. r. M 4 a | | J A] so N.|D.| tou 
| ale 
Observer: KE. F. v. p. S. BAKHUYZEN. 
ae 15 28 | a | so | 17 | a s/t v0 | 98 | 2 19 | 256 
dam, | 8 | 20/9 soja ss 5 | 98 | us) wa 
Observer: J. H. WILTERDINK. 
Wp. |E EEE jn | 
GR, | 18 90 | 92 49 10 | 9 | 13 ee 20 u | 274 
coal ra 
ed a 9 | 20/38) 20 ao sean | | a | | | 286 
| L 
4, The following remarks may help to form an opinion about the 
value of this material for the investigation of the motion of the pole : 
ist. The mean value of the accidental error in the azimuth, de- 
duced from one transit-observation, is two or three times greater than 
the amplitude of the 14-monthly motion. 
ged, The directions of the marks in the horizontal plane are by 
no means absolutely stable, on the contrary their accidental varia- 
tions throughout the whole period have been greater than the variation 
of the direction of the meridian resulting from the motion of the pole. 
3rd, In spite of the remarks 1 and 2, the number of the obser- 
vations and their distribution over a long period may lead us to 
expect a satisfactory determination of the periodical influences on the 
azimuth. 
Yet for an independent determination of the length of the period, 
the time during which the observations were made was too short. 
Therefore I had to content myself with a determination of the ampli- 
tude and the epoch. 
Besides the accidental variations the two directions of the marks 
are liable to systematic yearly-periodical motions in azimuth, as 
is clearly proved by the differences in azimuth of the two directions, 
which are of course independent of the motion of the pole. The graphi- 
cal representation of this periodical variation (Fig. 1) has been deduced 
from the readings of the marks from 1883 Aug. 10—189S Aug. 10. 
