A thermopile consisting of Chromelp‐constantan junctions is described. Since the thermoelectric power of this couple is relatively high (over 60 microvolts per degree C) and since the metals have a low thermal conductivity and are easily worked, a sensitive, rugged thermopile may be constructed to meet individual needs in a short time without previous experience. A very simple technique of construction is described and the characteristics of a finished instrument are given.