The aerodynamic resistance of wires. The apparatus used in these experiments was described by the author in his f Report to the Laboratory Committee of the Aeronautical Society of Great Britain. When the experiments herein described were started in 1910 no information on the resistance of wires and ropes was available, but the following papers have since been published :— “ The Resistance of Wires and Ropes in a Current of Air,” by B. Melville Jones, B.A. ; “ Comparison of the Resistances of Stationary and Vibrating Wires,” by T. E. Stanton, D.Sc, M.I.C.E. (Report of the Advisory Committee for Aeronautics, 1910-11) ; and “ The Tests of Smooth Wires and Wire-ropes made at the Gottingen “ Modellversuchsanstalt “ (Ztsch. fur Flugtechnik und Motorluftschiffahrt, Oct. 29th, 1910). Owing to the absence of funds the experiments of the resistance of wires have not been carried to a conclusion. The following data and conclusions are derived from a series of preliminary or trial experiments. They are published herewith for the guidance of future experimenters.