In our industrial life of to-day there are a vast number of instances where fuel oil is rapidly displacing coal: the oil-fired furnace has been brought to a stage of perfection, and is being extensively and increasingly employed both in this country and abroad in regard to metallurgical and industrial processes. Without going into detail respecting the numerous spheres in which the new fuel finds profitable employment it is safe to say that these are being extended every year. [Illustration: OIL FUEL FOR MARINE PURPOSES Arrangement of heaters, filters and pumps for burning oil fuel for marine purposes. The installation is that of the Wallsend-Howden pressure system.] A wealth of inventive effort has been bestowed in the perfection of the burners employed to consume fuel oil. Leaving aside for the moment the principles governing the use of oil in the internal combustion engines of the Diesel or semi-Diesel type, fuel oil used for the production of power is introduced into the furnace in the form of a spray, this being accomplished by atomizing the oil in its passage through a specially designed burner. Of these burners, there are numerous makes upon the market, each of which possesses its own characteristics and advantages. The one feature common to all fuel oil burners is the arrangement for atomizing the oil fuel into a fine spray, so that each particle of fuel shall receive sufficient oxygen to ensure its complete combustion. Theoretically, it requires about 14 lb. of air to effect the combustion of 1 lb. of oil, and on the thorough combustion of the fuel oil depends the efficiency of the furnace. There are three distinct methods by which the atomization is brought about, and each of these means possesses its advantages and limitations. By one method, the fuel oil is atomized by the use of steam; by the second method, compressed air is used; while a third system--that of applying pressure to the oil supply itself--is sometimes adopted. Steam is the method usually employed for stationary boilers and locomotives, for it is the simplest to manipulate, and does not call for the employment of auxiliary apparatus in the shape of air compressors or oil pumps, but most industrial oil furnaces work on compressed air, which gives exceptionally good results. There is no doubt that, with the use of compressed air, say admitted at a pressure of 80 lb., a saving in fuel oil is shown over using steam at similar pressure, but the cost of the compressing plant, which must be taken into consideration, is sufficient to wipe out the greater part of this advantage. [Illustration: THE “SCARAB” OIL BURNER]