other inventions.


What is a Microphone?

This instrument is a variety of telephone by means of which faint
sounds can be heard at a very great distance. It consists of a small
battery for generating a weak current of electricity, a telephone for
the receiving instrument, and a speaking or transmitting instrument.
The last is a small rod of gas carbon with the ends set loosely in
blocks of the same material. The blocks are attached to an upright
support, glued into a wooden base board. This instrument is connected
with the battery and the telephone. So wonderfully sensitive is it,
that the ticking of a watch, the walking of a fly across a board, or
the brush of a camel's-hair pencil can be heard even though it be
hundreds of miles distant.


Will you describe the Megaphone?

It is a substitute for the ear and speaking trumpet. It consists of
three paper funnels placed side by side. The two larger ones are about
6 feet 8 inches long and 27-1/2 inches in diameter, and are each
provided with a flexible tube, the ends of which are held to the ear.
The centre funnel, which is used as a speaking-trumpet, does not
differ materially from an ordinary trumpet, except that it is larger
and has a larger bell mouth. Two persons, each provided with a
megaphone, can, without other apparatus, carry on a conversation at a
distance of one and a half or two miles.