Dr. G.M. Sternberg's electro-magnetic regulator, for dampers and valves: secured by letters patent, No. 100.462, No. 105.272. and No. 105.273

Dr. G.M. Sternberg's electro-magnetic regulator, for dampers and valves: secured by letters patent, No. 100.462, No. 105.272. and No. 105.273