344 Mr. Christie on the diurnal deviations of the 
force acting upon the needle from the centre upwards to- 
wards the south ; the other below the needle with its south 
pole towards the centre, to destroy a corresponding portion 
of the force from the centre downwards towards the north : 
that is, both the magnets having their north poles down- 
wards. To prevent any ambiguity, I must here state, that, 
by the south pole of a magnet, I understand always the end 
which, when the magnet is freely suspended, points towards 
the north pole of the earth ; so that the north end is the south 
pole, and the south end the north pole of a magnetic needle. 
By diminishing the distances of the magnets from the centre-, 
I diminished the directive force of the needle until I destroyed 
it, after which, by diminishing the distances, I increased the 
force by which the north end was directed towards the 
south. 
Previously to giving any of the observations, to avoid un- 
necessary repetition, I will here state that, whenever the 
direction of the needle, or its deviation, or the direction of 
the forces urging it, is mentioned, reference is always made 
to the end of the needle which, when undisturbed, points 
towards the north, that is its south pole, unless the contrary 
is expressed. To compare more readily with each other, 
the directions of the deviations when the needle is held in 
different positions by means of the magnets, whenever the 
direction itself of the north end of the needle is not given, I 
consider the deviations which take place in the direction of 
the westerly, or principal daily variation to be plus, and those 
in a contrary direction minus : that is, in stating the devia- 
tions from any point, considered as zero, those which take 
place, from that point, in the direction of the sun's apparent 
