Abstract: A furnace and burner construction and method of burning fuel therein. The furnace housing has an end wall and side walls extending generally perpendicularly from the end wall and defining a furnace interior. One or more air supply ports open axially thereof through the end wall, and at least one fuel supply port opens axially thereof through the end wall and is spaced from the air supply port or ports. The air supply port is spaced from the side walls. When generally conical surfaces of jets of fuel and air are injected into the interior of the furnace through the air supply port or ports and the fuel supply port for carrying out burning of the fuel, recirculating currents of combustion products from the burning of the fuel are formed in the space between the jets and the side walls or between the jets themselves to lower the temperature of the burning.