Anemometer signifies a mechanical instrument for ascertaining the power and velocity of the wind.

Successful methods have discovered to determine, with in, the various properties of the air, its temperature. and weight, by means of the thermometer, the hygrometer, and the barometer; but, till lately, no tempts have been made to ascer-the force of the wind. Several instruments for this purpose have, indeed, been contrived; but they are in general more compli-. cated, and less to be depended on, than the machine which. describe under the head of Anemoscope.