IT IS a well-established fact that temperature can be measured by observing the change in resistance of a given material whose resistivity is a function of temperature. This principle of temperature detection is utilized in present-day resistance-type thermometers which commonly are called “aircraft thermometer bulbs.” When used in conjunction with the proper indicating instrument, the resistance-type thermometer provides an accurate system for furnishing information to the instrument panel on temperatures at remote points in an aircraft. This information is transmitted in the form of changes in electric current that are caused by variations in the electrical resistance of the temperature-sensitive element.