The Dry and Wet Bulb Thermometers “Froude”

Abstract

A SO-CALLED thermometer “froude” has been used in France for many years, and its use, on special occasions, has gradually extended to other countries. It consists of an ordinary thermometer fastened to a string two to four feet in length. If such a thermometer be swung through a circle whose radius is the length of the string, it is evident that it will attain the temperature of a large mass of air unless the results are vitiated by friction with the air, oxidation, centrifugal action, or other causes. Careful comparisons, at high and low velocities, with a thermometer properly exposed, have given entirely reliable results.