Western Electric Type 318-W "Chau-Phone" Microphone

Western Electric introduced a telephone system for the upscale automobile owner circa 1915.  A proper limousine of the day afforded little comfort for the chauffeur, who was exposed to the elements and separated from the owner by a barrier of wood and glass.  The "Chau-Phone" telephone system allowed the passengers to give directions to the chauffeur as he drove.  It was a one way system; the chauffeur was not expected to talk back to the passengers.

The system consisted of a hand-held carbon microphone, as seen here.  Internally, it was identical to the transmitter portion of a standard telephone.  A button on the side of the handle gave it a "push-to-talk" feature.  This prevented the chauffeur from eavesdropping, an ever-present danger.  A small horn loudspeaker was mounted in the driver's compartment.  It had to be positioned close to his ear, as no amplification was used.

The housing was black painted brass, and the mouthpiece was nickel plated.  The handle was either made of wood or hard rubber.  The same microphone was, I understand, sold as part of a public address system known as the "Shaw-Phone".

The notice on the back shows patent dates of Jan 14, 1913 (1,050,304) and Dec 8, 1914 (1,120,049). The first is the basic patent for the carbon microphone element inside, and the latter is for the overall design of the housing.
This is a page from a 1918 Western Electric catalog.  Click on the image for a larger view.