The low pressure air entering through opening (6) from the blower passes around the chamber (9) and mixes with the oil spray from (8) in the mixing chamber (7). This causes a violent swirl in (7) with the result that a comparatively intimate mixture of oil vapor and air is formed before they issue into the furnace. In many burners of this type a gauze screen (11) is placed over the mouth of the final orifice so that back fires are prevented and a still better mixture is formed. Many burners of this type have been built by the author with very satisfactory results, and he knows of only one weak point in the type. This is due to the fact that if a sufficient volume of air is not kept flowing through the low pressure pipe (6), the oil vapor may collect in the piping with the result a back fire will wreck all of the low pressure connections. To prevent this trouble a light galvanized iron weighted damper was placed beneath (6) which closed the pipe when the pressure fell below a certain amount. Since this check valve was placed there were no more pipe fires. In all cases a sliding damper should be placed in the opening so that the blast can be regulated to suit the amount of oil injected. As these burners were used in a closed building continuously without smoke or smell and with indifferent grade of oil it will be seen that the combustion was as nearly perfect as could be expected with any type of oil burner. Several of these burners were made from ordinary steam pipe fittings without steam nozzle adjustment. While the burners shown are arranged to give a flat flame (with the exception of burner F) they may all be built for a circular flame by surrounding the injection nozzle with a suitable nozzle. A =ROSE= or circular flame is particularly desirable for a vertical boiler where it can be made to conform with the circular shell and apply the heat directly to the tube sheet through suitable fire brick baffles. A burner of the injector type shown by Fig. G, has been used by the Pennsylvania Railroad with a considerable degree of success. The steam enters the steam nozzle at (12) through the circular openings from which point it passes through the nozzle (13) and carries the oil from the air port (14). The mixture or spray of steam and oil passes out of the nozzle (15) into the furnace. The steam nozzle is threaded into the casing at (16), and is keyed to the bevel gear (17). Meshing with (17) is the bevel mounted on the vertical stem which terminates in a hand-wheel in the engineer’s cab. By turning the bevels, the nozzle turns in the casing threads causing it to move back and forth for the adjustment.