328 Mr. Barlow's observations and experiments on the 
the east, west, and, in short, in any position at pleasure, at 
least within certain limits, which will be pointed out as we 
proceed. 
For this it is only necessary, first, to deflect the needle by 
repulsion into any required position, and then, by means of 
another magnet, to modify its directive power, in the same 
way as when in its natural meridian. Or the same may be 
done by bringing two magnets with their contrary poles 
pointing inwards, and each opposite to the pole of the same 
name of the needle placed between them, and by a slight 
adjustment of the former to produce the deviation in question : 
or, which is perhaps still better, the opposing magnets may 
be brought into the actual direction of the dip, and then ad- 
justed to produce the deflection required. 
Having mentioned my ideas and first experiments to my 
colleague, Mr. Christie, and having expressed a wish that 
he would repeat them for the sake of verification, he very 
readily agreed to undertake a complete set, with the needle 
in its natural meridian, by means of a very delicate compass, 
and an apparatus he had employed for other experiments, 
and which admitted of his bringing his neutralizing magnets 
very exactly into the line of the dip. In the mean time I 
proposed to undertake the observations on the dipping needle, 
and on the horizontal needle in different directions ; viz. with 
its north end pointing to the south, east, west, &c. Having, 
however, met with some embarrassment in the commence- 
ment, and having employed, in consequence, a longer time in 
the observations than I had anticipated, Mr. Christie, after 
having finished his observation in the meridian, continued 
them at other points, and has thereby detected several curj- 
