“i 
Fig. 1 
=H Gel 60 on Ge or) RR > zt = <H of —H 
. . tf 5 
a BO AP teed |. 5 3 Ee 5 2 5 be 5 b 
5 5 2 2 3 2 5 © 5 Ey 5 je 3 
ad < DQ 5) A =) = > = x = > 5 
lor] co oo oo ~ oo De ~ ~ o for) oo 
= re (J ama, Lan, ea ei re Lam md a ec 
. . | 
zr ep = + > 3 ; 5 © = be ® 
a 5 AOA or 9 eelt [ mc a & 5 
> <q ua ©) ea A > Zo ei <x qt => 
One part of this periodical annual variation is caused by a motion 
of the direetion of the north mark, another part by a similar motion 
in the direction of the south mark, and probably the mean azi- 
muth of the two directions is also influenced by the same motion: 
As communicated in § 3 the determinations of azimuth from 
1882 July to the end of 1883 concerned the north mark only; 
in order to be able to unite the azimuth of this period with those 
of the following years to a system as homogeneous as possible, 
the azimuths of the north mark before 1894 are diminished by half 
the difference in azimuth between the two directions from fig. 1; 
after having applied this correction, the remaining influence of the 
periodic motion on the azimuth of the north mark, is equal to that 
on the mean azimuth of both marks. | 
In the azimuths this influence is combined with that of the 
periodie motion of the meridian direction, resulting from the yearly- 
periodical part of the motion of the pole; as we cannot compute 
the two influences separately, we cannot compare these determina- 
