We describe the results of 357 experimental fires conducted in an environmentally controlled large wind tunnel. The fires were burned over a range of particle sizes, fuel bed depths, packing ratios, moisture contents and windspeeds. We find that spread rate decreases with moisture content in a way which depends on the fuel type and diameter. It decreases as the square root of the packing ratio. Fuel bed depth has little effect on spread rate, and fuel diameter has significant effect only for diameters above 1 mm. The relationship between rale or spread and windspeed is virtually linear