' 374 Mr. Christie on the magnetism of 
To ascertain how far my views were correct, or otherwise, 
I adjusted the plate on the arm as in fig. 6 . the same as in 
the last experiments, and the instrument as in fig. 2 : so that 
the axis being in the plane of the meridian and inclined 
to the horizon at an angle of 19° so', the centre and plane of 
the plate were, during the revolution of the limb, always in 
the position I required. The distance between the centres of 
the needle and plate was as before 13.2 inches. The follow- 
ing Table exhibits the observations which I made ; the letters 
at the tops of the columns indicate the direction of rotation 
of the plate's inner edge ; and the numbers in the first column, 
the points on the plate which coincided with the plane of the 
secondary, when the several directions of the north end of 
the needle in the same lines with them were observed. The 
observations were made at every 10° of latitude, as in some 
cases there was an indication of deviation due to rotation. 
