nd a local adjustment of particles, or fluids, or
forces, not progressive. Many other reasons might be urged in support of
the view of a _current_ rather than an _arrangement_, but I am anxious to
avoid stating unnecessarily what will occur to others at the moment.

II. _Ordinary Electricity._

284. By ordinary electricity I understand that which can be obtained from
the common machine, or from the atmosphere, or by pressure, or cleavage of
crystals, or by a multitude of other operations; its distinctive character
being that of great intensity, and the exertion of attractive and repulsive
powers, not merely at sensible but at considerable distances.

285. _Tension._ The attractions and repulsions at sensible distances,
caused by ordinary electricity, are well known to be so powerful in certain
cases, as to surpass, almost infinitely, the similar phenomena produced by
electricity, otherwise excited. But still those attractions and repulsions
are exactly of the same nature as those already referred to under the head
_Tension, Voltaic electricity_ (268.); and the difference in degree between
them is not greater than often occurs between cases of ordinary electricity
only. I think it will be unnecessary to enter minutely into the proofs of
the identity of this character in the two instances. They are abundant; are
generally admitted as good; and lie upon the surface of the subject: and
whenever in other parts of the comparison I am about to draw, a similar
case occurs, I shall content myself with a mere announcement of the
similarity, enlarging only upon those parts where the great question of
distinction or identity still exists.

286. The discharge of common electricity through heated air is a well-known
fact. The parallel case of voltaic electricity has already been described
(272, &c.).

287. _In motion._ i. _Evolution of heat._--The heating power of common
electricity, when passed through wires or other substances, is perfectly
well known. The accordance between it and voltaic electricity is in this
respect complete. Mr. Harris has constructed and described[A] a very
beautiful and sensible instrument on this principle, in which the heat
produced in a wire by the discharge of a small portion of common
electricity is readily shown, and to which I shall have occasion to refer
for experimental proof in a future part of this paper (344.).

[A] Philosophical Transactions, 1827, p. 18. Edinburgh Transactions,
1831. H