The first part of this report presents the results of further tests of fires in wood cribs. In one series of tests cribs of the same height and structure but with different areas, or horizontal cross-sections, were burned in still air to determine the effect of size of burning area on the rate of burning per unit area. A second group of tests in still air concerns the effect of stick size and spacing on rate of fire spread. A third series of tests was made with fires in the wind tunnel to determine the effect of wind speed on rate of spread, rate of heat output, flame length, and angle of flame tilt. Although a quantitative model of fire propagation is not proposed, the second part of the report deals with mechanisms of fire spread. An experiment with a series of pool fires in wind stream is described which illustrates an important ignition process involved in the spread of wind-driven fires.