Fahnestock Electric Co.; Long Island City, NY.
Manufacture of different connectors and clamps.

U.S. Patent No. 1,163,371 for the Fahnestock clip was issued December 7, 1915, to Fahnestock Electric Company of New York (John Schade, Jr., Assignor) more than 3 1/2 years after the filing date (May 22, 1912). Almost eight more years elapsed, however, before the device was first advertised in Radio News (November 1923, p. 637). "Fahnestock connectors" where listed in the 1922 catalog of the Manhatten Electrical Supply Company (MESCO) for "experimenters who are particularly interested in the construction of rough laboratory circuits" (p. 192). By 1922, Fahnestock clips began to appear on commercial crystal sets and crystal detectors, but binding posts continued to be used widely for several more years.
Source : "Crystal Clear, Vol. 1 by M.L. Sievers, p. 10.