or of many improvements in telegraphy, which have been adopted
into general use, and are to him the source of a large income. To him,
also, we are indebted for the megaphone, microphone, tasimeter, an
improvement in the telephone, a system of electric lighting, and many
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.

What is the Tasimeter?

It is an instrument, sensitive to the smallest degree of heat, and is
mostly used in astronomy. Attached to a telescope it will show the
heat coming from the stars.

What is a Bathometer?

This ingenious instrument, the invention of Prof. Siemens of London,
enables those on board of ships to read from an index the depths of
the ocean beneath them. It consists of a highly sensitive steel spring
to which a heavy piece of metal is attached. The changes in weight to
which the latter is subject in consequence of the variations of
attractive force (the deeper the ocean the smaller the latter, and
vice versa) are registered on a scale by the indicator that is in
connection with the steel spring.

What is an Anemometer?

An instrument for measuring the velocity and force of