ration of the mica diaphragm to which the stylus was attached.
Thus the undulatory current was able to establish vibrations of the
disc, which communicated themselves to the air and reproduced the
original sounds. The replica was loud enough to be heard by a large
audience, and by reducing the strength of the current it could be
lowered to a feeble murmur. The combined transmitter and receiver took
the form of a small case with a mouthpiece to speak into, an car-piece
on a hinged bracket for listening to it, press-keys for manipulating the
call-bell and battery, and a small handle by which to revolve the
little chalk cylinder. This last feature was a practical drawback to the
system, which was patented in 1877.

The Edison telephone, when at its best, could transmit all kinds of
noises, gentle or harsh; it could lift up its voice and cry aloud, or
sink it to a confidential whisper. There was a slight Punchinellian
twang about its utterances, which, if it did not altogether disguise the
individuality of the distant speaker, gave it the comicality of a clever
parody, and to hear it singing a song, and quavering jauntily on the
high notes, was irresistibly funny. Instrumental notes were given in all
their purity, and, after the phonograph, there was nothing more magical
in the whole range of science than to hear that fragment of common chalk
distilling to the air the liquid melody of sweet bells jingling in tune.
It brought to mind that wonderful stone of Memnon, which responded
to the rays of sunrise. It seemed to the listener that if the age of
miracles was past that of marvels had arrived, and considering the
simplicity of the materials, and the obscurity of its action, the
loud-speaking telephone was one of the most astonishing of recent
inventions.

After Professor Hughes had published his discovery of the microphone,
Edison, recognising, perhaps, that it and the carbon transmitter were
based on the same principle, and having learnt his knowledge of the
world in the hard school of adversity, hastily claimed the microphone as
a variety of his invention, but imprudently charged Professor Hughes and
his friend, Mr. W. H. Preece, who had visited Edison at Menlo Park, with
having 'stolen his thunder.' The imputation was indignantly denied, and
it was obvious to all impartial electricians that Professor Hughes
had arrived at his results by a path quite independent of the carbon
transmitter, and discovered a great deal more