Acting
on this knowledge, he constructed a rude telephone.
Dr. Messel informs us that his first transmitter consisted of the bung
of a beer barrel hollowed out in imitation of the external ear. The cup
or mouth-piece thus formed was closed by the skin of a German sausage to
serve as a drum or diaphragm. To the back of this he fixed, with a drop
of sealing-wax, a little strip of platinum, representing the hammer-
bone, which made and broke the metallic circuit of the current as the
membrane oscillated under the sounds which impinged against it. The
current thus interrupted was conveyed by wires to the receiver, which
consisted of a knitting-needle loosely surrounded by a coil of wire
fastened to the breast of a violin as a sounding-board. When a musical
note was struck near the bung, the drum vibrated in harmony with the
pitch of the note, the platinum lever interrupted the metallic circuit
of the current, which, after traversing the conducting wire, passed
through the coil of the receiver, and made the needle hum the original
tone. This primitive arrangement, we are told, astonished all who heard
it. [It is now in the museum of the Reichs Post-Amt, Berlin.]
Another of his early transmitters was a rough model of the human ear,
carved in oak, and provided with a drum which actuated a bent and
pivoted lever of platinum, making it open and close a springy contact of
platinum foil in the metallic circuit of the current.
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