Western Electric 371W Carbon Microphone
The Western Electric model 371W microphone dates to the early 1920's, and was used in public address, broadcast, and other radio applications.  The element is a double button carbon design, mounted in a telephone-type stand.  This particular microphone had a nickel plated shell, others of the same type were painted black.  The most recent patent date shown on the unit is March, 1920.

This photo from a late 1920's Western Electric public address equipment catalog shows a theatre installation using a microphone similar to this one (the picture isn't clear enough to be certain of the model).  Click here or on the picture for a larger view.