ion of which puts extra lengths of
tubing in connection with the main tube--in fact, makes it longer. One
key lowers the fundamental note of the horn half a tone; the second, a
full tone; the third, a tone and a half. If the first and third are
pressed down together, the note sinks two tones; if the second and
third, two and a half tones; and simultaneous depression of all three
gives a drop of three tones. The performer thus has seven possible
fundamental notes, and several harmonics of each of these at his
command; so that by a proper manipulation of the keys he can run up the
chromatic scale.

We should add that the cornet tube is an "open" pipe. So is that of the
flute. The clarionet is a "stopped" pipe.

[29] It is obvious that in Fig. 136, _2_, a pulse will pass from A to B
and back in one-third the time required for it to pass from A to B and
back in Fig. 136, _1_.

[30] The science of hearing; from the Greek verb, [Greek: akouein], "to
hear."

[31] "Organs and Tuning," p. 245.

Chapter XVI.

TALKING-MACHINES.

The phonograph--The recorder--The reproducer--The gramophone--The
making of records--Cylinder records--Gramophone records.

In the Patent Office Museum at South Kensington is a curious little
piece of machinery--a metal cylinder mounted on a long axle, which has
at one end a screw thread chased along it. The screw end rotates in a
socket with a thread of equal pitch cut in it. To the other end is
attached a handle. On an upright near the cylinder is mounted a sort of
drum. The membrane of the drum carries a needle, which, when the
membrane is agitated by the air-waves set up by human speech, digs into
a sheet of tinfoil wrapped round the cylinder, pressing it into a
helical groove turned on the cylinder from end to end. This construction
is the first phonograph ever made. Thomas Edison, the "wizard of the
West," devised it in 1876; and from this rude parent have descended the
beautiful machines which record and reproduce human speech and musical
sounds with startling accuracy.

[Illustration: FIG. 146.--The "governor" of a phonograph.]

We do not propose to trace here the development of the talking-machine;
nor will it be necessary to describe in detail its mechanism, which is
probably well known to most readers, or could be mastered in a very
short time on personal examination. We will content ourselves with
saying that the wax cylinder of the phonograph, or the ebonite di