IN Engineering of May 26 is an illustrated article on the large hydraulic laboratory recently completed on the Mississippi River at St. Anthony Falls, Minneapolis, for the University of Minnesota. The laboratory is on Hennepin Island, which is joined to the banks of the river by a dam constructed for the purpose of power development at the falls, and it is designed to operate practically entirely by water diverted above the falls. There is a natural drop of fifty feet and the laboratory can handle for experimental purposes rates of flow in excess of 300 cusecs. Flows up to this amount can be accurately measured by volumetric basins. The laboratory consists of five units, namely, the main experimental laboratory, the hydraulic machinery and pump laboratory, the turbine testing laboratory, the large-scale volumetric tanks, and the lecture room and administration rooms. In the first of these units is a river model section where at present there is under construction a working model, 160 ft. long and 36 ft. wide, of the Mississippi in the vicinity of St. Anthony Falls. The lecture room has been arranged so that large quantities of water can be handled readily at the platform. Below the platform runs the main overhead supply flume of the laboratory, while above it is a head control room containing a constant-level reservoir situated in the tower above the auditorium. The experimental flume which runs through the main laboratory can be used for experiments with ship models.