25] are most easily rendered
perceptible with the help of the previously described wire loops. To
focus attention on just one of the windings of Figure 3, we sketch a
new drawing, Figure 5.... Since it is of major importance that these
loops be made of silk-covered wire lying evenly on one another, it
is convenient to wind the loops on two small slotted sticks of wood,
although it is also possible to hold the wires together with wax or
shellac, or to tie them together in an orderly manner with silk
thread....

In Figure 5, Aa and Cc represent little slotted rods of wood on
which the silk-covered wire is wound. Only three windings are shown
in the figure, but I generally adopt three times that many. Now t is
connected with the copper and d with the zinc, and the compass B set
between the rods Aa and Cc with the coil perpendicular to the
magnetic meridian and the terminals d, t at the east.

The instant Z and K are dipped in the ammonium chloride solution,
the needle turns around and stays with the north pole point
south....

If now the compass is taken out of the coil and put in position b,
all effects are reversed, and are considerably weaker, for obvious
reasons....

It is of the same significance whether we bring the compass from B
to b in Figure 5, or from mesh 1 to mesh 2 in Figure 3, only that in
the latter case, because the compass is enclosed by the two sides, a
stronger effect results....

If now the coil is rotated ... so that the face previously north now
faces south, then on connecting the electric circuit there is
absolutely no trace of effect on the needle, assuming that the
terminal wires are not reversed....

It seems unnecessary to note that our magnetic coil can be placed in
the direction of the magnetic meridian or at any arbitrary angle
with it....

Following several pages of further talk about the relation of "cohesion
to magnetism" and about "unipolar and bipolar conductors," the only
additional item of interest is the observation that discharges of a
Leyden jar (_Kleistichen Flasche_) strong enough to burn strips of leaf
gold and to magnetize an iron rod in a coil, produced no compass-needle
deflections, even with the help of the "amplifying apparatus."

Schweigger, therefore, described the basic multiplier idea clearly
enough in his first paper, but offered no sketc