CHARACTERISTICS OF PYROMETRIC CONES1

For the first time the characteristics of pyrometer cones have been determined under definite and reproducible conditions of heating. The temperatures of the “end points” of a complete set of cones together with their bending intervals were measured at carefully controlled rates of heating in clean air and in various kiln gases. Heated at 20°C per hour in furnace gases free from SO₂, the end points of cones 015 to 01 are somewhat higher than those observed when the cones were heated in clean air. Cones 022 to 016 and 1 to 42 were acted upon only slightly by kiln gases free from SO₂. There is more significance in the demonstration of the utility of measuring the end points of the cones under accurately controlled and known conditions of heating than in the numerical results obtained.