wire, Figure 3.
[There were no illustrations with Schweigger's first paper.] While
a single wire, using the weak electric circuit here, deflects the
magnetic needle only 30 deg. or 40 deg., if the compass is placed in
one of the openings of this pattern, the needle is deflected 90 deg.
to the east, or in the other opening 90 deg. to the west, using the
same weak electric circuit....

The "bow-pattern" device has novelty interest only, adding nothing to
the elucidation of the multiplier phenomenon. The same is true of
Schweigger's next proposal, shown in figure 4. "... I will now add
another apparatus, which is just an extension of the previous one,
whereby the needle can take up any angle from 0 deg. to 180 deg." A short
length of circular glass tubing, of inside diameter large enough to
contain a compass needle, stands with its axis vertical and has single
or multiple loops of wire wound on it in vertical diametral planes. In
the illustration, successive plane coils are inclined at 30 deg. to one
another. "... the electric current flows through the whole wire, and the
needle moves under all of these currents, and coming always into another
loop can take any desired angle."

With much further theorizing about "the correlation of magnetism with
the cohesion of bodies," Schweigger states again his evaluation of his
discovery: "Oersted succeeded in electromagnetic research by using a
spark-producing cell, which could make a wire glow. My amplifying
electromagnetic device needs only a weak circuit of copper, zinc, and
ammonium chloride solution."[24]

[Illustration: Figure 4.--SCHWEIGGER MADE THIS peculiar construction of
wire coils, wound endwise on a short vertical section of glass tubing
with a compass needle inside, merely to startle his Halle audience with
the fact that the compass needle could rest in any of several stable
positions. (From _Journal fuer Chemie und Physik_.)]

[Illustration: Figure 5.--SCHWEIGGER'S SUGGESTION of one possible design
for an amplifying electromagnetic indicator. The components are wooden
rods and insulated wire. Position b referred to in the text is at the
bottom of the diagram between the letters a and c. (From _Journal fuer
Chemie und Physik_.)]

"FURTHER WORDS ABOUT THE NEW MAGNETIC PHENOMENA"

[This was presumably written between November 4, 1820, and the January
1, 1821, publication date of his _Journal_.]

These wonderful new electrical effects[