BLDG BLOG unearths a fascinating article from 1898, on the Brazilian Indian Telephone.

These natives live in groups of from one hundred to two hundred persons, and in dwellings called "maloccas," which are usually situated at a distance of half a mile or a mile apart. In each maloccathere is an instrument called a "cambarisa," which consists essentially of a sort of wooden drum that is buried for half of its height in sand mixed with fragments of wood, bone, and mica, and is closed with a triple diaphragm of leather, wood, and India rubber. When this drum is struck with a wooden mallet, the sound is transmitted to a long distance, and is distinctly heard in the other drums situated in the neighboring maloccas. The blows struck are scarcely audible outside of the houses in which the instruments are placed. After the attention of the neighboring maloccas has been attracted by a call blow, a conversation may be carried on. … The communication is facilitated by the nature of the ground, the drums doubtless resting upon one and the same stratum of rock.