in linear relation to temperature radiation responds in proportion to the fourth power of temperature and provides an additional and stabilizing factor to the heat transfer rate the temperature of the burned gases increases until the heat of combustion equals the heat losses for natural gases the gas temperature reaches radiation frequencies in the visible spectrum and the flame is visible in the present invention gas flow rates and volumes through the combustion apparatus 8 are also limited by design to limit the total available heat of the combustion reaction if the energy available from combustion is too great electrical power cannot be reduced enough to control the combustion therefore limits are placed on the flow rates and volumes of the gas air mixture to limit the heating power available by combustion to less than the electrical power required to heat the solid material 26 above the auto ignition temperature the solids structure surrounding the small voids allows the heat transfer rate between the combustion gas products and the heater to be sufficiently high to prevent large temperature increases and thereby stabilize the combustion temperature the body of material 26 must have sufficient heat transfer capacity to quench the flame without requiring high radiation temperatures the air and the gas are introduced at the base of the column 25 and travel through the ceramic material 26 due to heat flow from the.