The contact between
the rod and the block in this 'hammer-and-anvil' form is, of course, the
portion which is sensitive to sound.
The microphone is a discovery as well as an invention, and the true
explanation of its action is as yet merely an hypothesis. It is
supposed that the vibrations put the carbons in a tremor and cause them
to approach more or less nearly, thus closing or opening the breach
between them, which is, as it were, the floodgate of the current.
The applications of the microphone were soon of great importance. Dr.
B. W. Richardson succeeded in fitting it for auscultation of the heart
and lungs; while Sir Henry Thompson has effectively used it in those
surgical operations, such as probing wounds for bullets or fragments of
bone, in which the surgeon has hitherto relied entirely on his delicacy
of touch for detecting the jar of the probe on the foreign body. There
can be no doubt that in the science of physiology, in the art of
surgery, and in many other walks of life, the microphone has proved a
valuable aid.
Professor Hughes communicated his results to the Royal Society in the
early part of 1878, and generously gave the microphone to the world.
For his own sake it would perhaps have been better had he patented and
thus protected it, for Mr.
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