This voltmeter consists of a vertical plunger-type (solenoid) potential indicator having a scale with a single index mark to which the instrument pointer may be set by means of an adjustable vertical rheostat, calibrated in volts. Numbered every 5 downward from 90 to 120. It is mounted in a wooden case with a glass top. Marked, "Westinghouse Electric & Mfg. Co., Lang & Shallenberger [serial number] 1909". Brass plate in back reads: " Westinghouse Elec. & Mfg Co. Pittsburgh Pa. / Patented Lauge Jul. 12 '87, Jul. 31 '88 Aug. 12 '90/ Lauge & Shallenberger / July 12 '87" Stamped in frame: " No.1909". One of these instruments was provided for use in a station as a standard. Not regularly used in the circuit, but could be connected in the circuit at any time to check the accuracy of the regular service meter used to maintain permanent accuracy and uniform service. Cover not in place, pointer bent & broken off.