e in _all_ directions by
the tension and reaction of those which are contiguous. The transverse
force is merely this relation considered in a direction oblique to the
lines of inductive force, and at present I mean no more than that by the
phrase. With respect to the term _polarity_ also, I mean at present only a
disposition of force by which the same molecule acquires opposite powers on
different parts. The particular way in which this disposition is made will
come into consideration hereafter, and probably varies in different bodies,
and so produces variety of electrical relation[A]. All I am anxious about
at present is, that a more particular meaning should not be attached to the
expressions used than I contemplate. Further inquiry, I trust, will enable
us by degrees to restrict the sense more and more, and so render the
explanation of electrical phenomena day by day more and more definite.

[A] See now 1685. &c.--_Dec. 1838._

1305. As a test of the probable accuracy of my views, I have throughout
this experimental examination compared them with the conclusions drawn by
M. Poisson from his beautiful mathematical inquiries[A]. I am quite unfit
to form a judgment of these admirable papers; but as far as I can perceive,
the theory I have set forth and the results I have obtained are not in
opposition to such of those conclusions as represent the final disposition
and state of the forces in the limited number of cases be has considered.
His theory assumes a very different mode of action in induction to that
which I have ventured to support, and would probably find its mathematical
test in the endeavour to apply it to cases of induction in curved lines. To
my feeling it is insufficient in accounting for the retention of
electricity upon the surface of conductors by the pressure of the air, an
effect which I hope to show is simple and consistent according to the
present view[B]; and it does not touch voltaic electricity, or in any way
associate it and what is called ordinary electricity under one common
principle.

[A] Memoires de L'Institut, 1811, tom. xii. the first page 1, and the
second paging 163.

[B] Refer to 1377, 1378, 1379, 1398.--_Dec. 1838._

I have also looked with some anxiety to the results which that
indefatigable philosopher Harris has obtained in his investigation of the
laws of induction[A], knowing that they were experimental, and having a
full conviction of their exactness; but I am happy in