demonstrate clearly that heat and electricity are as closely allied;
then, knowing the great analogies existing between heat and light, may
we not find that heat, light, and electricity are modifications of
the same force or property, susceptible under varying conditions of
producing the phenomena now designated by those terms? For instance,
friction will first produce electricity, then heat, and lastly light.

As is well known, heat and light are reflected by metals; I was
therefore anxious to learn whether electricity could be reflected in
the same way. In order to ascertain this, spiral B was placed in this
position, which you will observe is parallel to the lines of force
emitted by spiral A. In this position no induced current is set up
therein, so the galvanometer is not affected; but when this plate of
metal is placed at this angle it intercepts the lines of force, which
cause it to radiate, and the secondary lines of force are intercepted
and converted into induced currents by spiral B to the power indicated
by the galvanometer. Thus the phenomenon of reflection appears to be
produced in a somewhat similar manner to reflection of heat and light.
The whole arrangement of this experiment is as shown on the sheet before
you numbered 5, which I need not, I think, more fully explain to you
than by saying that the secondary lines of force are represented by the
dotted lines.

Supported in this wooden frame marked C is a spiral similar in
construction to the one marked B, but in this case the copper wire is
0.044 inch in diameter, silk-covered, and consists of 365 turns, with
a total length of 605 yards; its resistance is 10.2 ohms, the whole is
inclosed between two thick sheets of card paper. The two ends of the
spiral are attached to two terminals placed one on either side of the
frame, a wire from one of the terminals is connected to one pole of a