[Illustration:  FIG. 1. 
               FIG. 2. 
               FIG. 3. 
       THE MIX AND GENEST TELEPHONE]

In all such cases the regulating contrivance applied to brake the carbon rollers in their motion has the result that only the oscillations transmitted from the sound plate on to the contacts come in operation, whereas disturbing mechanical shocks resulting from any outward influences occasion very insignificant vibrations, which are not perceptible in the telephone.  The separate contacts thus form a firm system with the sound plate, so that the former are influenced in their motions and effects solely and alone by the shocks and oscillations which operate direct on these sound plates.  The roller motion of the carbon is thus removed, and the distinctness of the words spoken is greatly augmented.

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 the distinctness of the human voice are clearer and far more intelligible.  One simple regulation of the microphone suffices for the installation, for there is no danger of its getting out of order.  Owing to its peculiar construction, this new microphone is very firm and solid, and for this very reason offers another advantage, namely, the possibility of transmitting sound over very long distances.  In the competitive trials instituted