The above Figs. 1 and 2 show the microphone in side view and in cross
section.

A metal ring, R (see Fig. 1), is fastened by means of the four screws,
_r_{1}_ _r_{2}_ _r_{3}_ _r_{4}_, on a wooden mouthpiece. In a recess of the
above ring is the diaphragm, M, which is provided on its outer edge
with an India rubber band and is held in position by the two clamps, _a_
and _a_{1}_. The diaphragm is cut out of finely fibered firwood and is
well lacquered to preserve it against dampness. On it there are two
carbon beams, _b_, and in the perforations of the latter are the
journals of the carbon rollers, _k_. The alterations in contact take
place in the touching points. The cross piece, _f_, that runs straight
across the carbon rollers serves as a braking contrivance, which is
regulated as may be necessary by the large projecting screws.

Fig. 3 shows the apparatus in cross section. T is the mouth piece, R
the metal ring, M the diaphragm, _f_ the breaking cross piece. On the
latter is a metal block fastened by means of two screws. On this metal
block is a soft elastic strip (d) of felt or similar material. The
letters _s_ and _s_ indicate the regulating screws for the braking
contrivance.

The excellent qualities of other microphones, in particular their
extreme sensibility for the very least impressions, are undeniable;
but it is just this sensibility that is the cause of the complaints
made by the public. In practical use this overgreat sensibility proves
to be a fault.

In the apparatus constructed by Messrs. Mix and Genest the well-known
deficiencies of other systems are avoided. The effect of the sound and