Division F The Theory of Single Burbling.- Editor’s Preface.- Division G The Mechanics of Viscous Fluids.- Editor’s Preface.- Division H The Mechanics of Compressible Fluids.- Editor’s Preface.- I. The Propagation of Plane Disturbances.- II. Steady Flow through Channels.- III. Two-Dimensional Flow at Speeds Less than that of Sound.- IV. Two-Dimensional Flow at Supersonic Speeds.- Division I Experimental Methods—Wind Tunnels.- Editor’s Preface.- 1.- I. Classification of Methods—Use of Natural Winds.- II. Methods Using an Artificial Air Flow—Classification of wind Tunnels, Description, Energy Losses.- III. Influence of the Dimensions of the Air Stream.- 2.- I. Scale Effect.- II. The Variable Density Tunnel.- III Experimental Methods for the Investigation of Aerodynamic Phenomena at High Speeds.