This paper concerns an investigation of turbulence in the density stratified shear flow of a specially designed wind tunnel in which the density gradient is created by differential heating of the air. The first three sections of the paper consist of a description of the apparatus and of the mean temperature and velocity gradients in the tunnel, together with a discussion of a method of measuring low wind speeds based on the periodic shedding of vortices by a circular cylinder. In the remaining sections details of the experimentally determined structure of the turbulence of the flow and of its eddy conductivity and viscosity are presented and their dependence on the over-all gradient form of Richardson number, $[g \partial T | \partial z]|[T(\partial U| \partial z)^2]$, considered.