36 DR. FARADAY’S EXPERIMENTAL RESEARCHES IN ELECTRICITY. (SERIES XXVI.) 
2824. Besides these differences the bodies must have an equatorial condition, which, 
in the two classes of conductors, would be able to produce corresponding effects. The 
whole of the equatorial part of P (fig. 3) is alike in relation to the body P, or to the 
lines of force in the surrounding space ; and there is a like correspondence in the 
equatorial parts of D, either to itself or to space ; but these parts in P or in D differ 
in intensity of power one from the other, and both from the general intensity of the 
space. Such equatorial conditions must, I think, exist as a consequence of the defi- 
nite character of any given section of the magnetic field (2809.). 
2825. Though the experimental results of these polarities are not absent, still they 
are not very evident or capable of being embodied in many striking forms ; and that 
because of the extreme weakness of the forces brought into play, as compared with 
those larger forces exhibited in the mutual action of magnets. Hence it is, that the 
many attempts to show a polarity in bismuth have either failed, or other phenomena 
have been mistaken for those properly referable to such a cause. The highest, and 
therefore the most delicate, test of polarity we possess, is in the subjection of the 
polar body to the line of direction of magnetic forces of a very high degree, when 
developed around it ; and hence it is, that the pointing of a substance between the 
poles of a powerful magnet is continually referred to for such a purpose. It would 
be, and is utterly in vain to look for any mutual action between the poles of two 
weak paramagnetic or diamagnetic conductors in many cases, when the action of 
these same poles is abundantly manifest in their relation to the almost infinitely 
stronger poles of a powerful horseshoe or electro-magnet. 
2826. I took a tube a (fig. 4), filled with a saturated solution of sulphate Fig- 4. 
of cobalt, and suspended it between the poles of the great electro-magnet ; 
it set readily and well. Another tube, h, was then filled with a saturated 
solution of sulphate of iron, and being associated with the S pole of the 
magnet, was brought near the cobalt tube in the manner shown, but not 
the slightest effect on the position of a was observable. The tube b was 
changed into the position c, to double any effect that might be present, but 
no trace of mutual action between the poles of a and b was visible (2819.). 
2827. To increase the effect, the magnetic solution tube was suspended in water, 
as a good diamagnetic medium, between flat-faced poles (fig. 5). It 
pointed well. Two bottles of saturated solution of sulphate of iron 
were placed at t^and e, but they did not alter the position of a ; being 
removed into the positions f and g, neither was any sensible alteration 
of the position of a produced. I made the same kind of experiment 
with an air-tube in water, in which case it points axially (2406.), with 
the same negative result. I do not mean to assert that there was ab- 
solutely no effect produced in these cases (2819.) ; but if any, it must 
have been inappreciably small, and shows how unfit such means are to 
compare with those which are supplied by the pointing of a body when 
under the influence of powerful magnets. If polarity cannot be found by these 
Fig. 5. 
T/TT/AW/ 
YA 
