uses the Von Boden-Ingalls burnera shown in fig. 66. In front of the oil outlet is placed a corrugated lip, which retains any drippings from the burner, and is said to assist in atomizing the oil. The burner is placed in the front end of the fire-pan. Admission of air takes place through a number of horizontal tubes, placed under the burner, and these tubes can be covered by an external damper operated from the cab. The Von Boden-Ingalls burner is so arranged that oil may be taken in either at the top or bottom of the oil chamber, as is the more convenient. The opening not in use is closed by a plug.

Fig. 67 shows the arrangement of oil-burning locomotive equipment as used by the Baldwin Locomotive Works. It was formerly their practice to place the burner in the rear end of the furnace and burn the oil under a brick arch. In service, however, when the engine was being heavily worked, the draft frequently lifted the flame over the arch, thus causing incomplete combustion and an excessive amount of smoke. The horizontal draft arrangement with burner placed in the front end of the furnace has been found in practice to give very much better results.

Mr. Charles E. Kern is authority for the following statement: "The 80,000,000 barrels of fuel oil now used annually on the steam railroads of the country is reported to the Interstate Commerce Commission as 20,000,000 tons of coal and is equivalent to one-seventh, speaking roughly, of the entire fuel requirements of the railroads of the United States. This estimate is made upon the basis of statistics for the first six months of 1919. During these six months the steam railroad freight service used 35,302,800 tons of coal or equivalent in fuel oil. The passenger service used 14,770,000 tons, switching service 10,187,000 tons, mixed special service 1,001,000 tons and stationary plants 8,200,000 tons. Double these figures and we have a total of about 140,000,000 tons of coal or its equivalent in fuel oil, and of the entire amount 20,000,000 tons was, in fact 80,000,000 barrels, of fuel oil. Thirty-six of the great steam railroad systems of the United States use in whole or in part fuel oil. The Central Western Division consumes annually about 21,500,000 barrels of fuel oil. This division includes the Santa Fe, Chicago, Burlington & Quincy, Northwestern & Pacific, Los Angeles, Salt Lake, Rock Island, Colorado Southern, Fort Worth & Denver City, Southern Pacific and the Arizona Eastern. The Northwestern region cona. Oil Burning Locomotives, The Baldwin Locomotive Works.

sumes about 6,250,000 barrels of oil as follows: Chicago & Northwestern, 1,000,000 barrels; Chicago, Milwaukee & St. Paul, 1,250,000 barrels; Great Northern, 1,900,000 barrels; Southern Pacific, 1,300,000 barrels; the Spokane, Portland & Seattle, 750,000 barrels; and the Northern Pacific, 275,000 barrels. The New York Central normally uses approximately 4,000,000 barrels of fuel oil annually and the Delaware & Hudson about 1,800,000 barrels. The Long Island road uses fuel oil. The Florida East Coast requires about 1,000,000 barrels; the Wichita Falls & Northwestern requires about 1,250,000 barrels; the Missouri, Kansas & Texas, 1,250,000 barrels; Gulf, Colorado & Santa Fe, 7,000,000 barrels; the Galveston Wharf, 250,000 barrels; Trinity & Brazos Valley, 900,000 barrels; Morgan's Louisiana & Texas, 6,000,000 barrels; Houston, Belt Terminal, 750,000 barrels ; Texas & Pacific, 10,000,000 barrels; Gulf Coast Lines, 5,000,000 barrels; St. Louis Southwestern, 5,000 barrels; Kansas City Southern, 1,000,000 barrels; International & Great Northern, 1,500,000 barrels; Fort Worth Belt Line, 50,000 barrels; St. Louis & San Francisco, 900,000 barrels; Missouri, Kansas & Texas Railway of Texas, 3,000,000 barrels, and the Gulf, Colorado & Santa Fe, 80,000 barrels."

CHAPTER XI

THE MANUFACTURE OF IRON AND STEEL

The importance of a nation depends upon its agricultural resources, its fuel deposits, and its iron deposits. It is a difficult matter to determine which of these resources is the most important or which has contributed most largely to the advance of a country. Undoubtedly the great industrial predominance

FIG. 68. Iron Ore Blast Furnace.

of the United States is due to the fact that this country is rich in all three resources. It is, however, possible that industrial prominence depends more upon iron deposits than upon the other two factors, because the foundation of our present industrial structure is steel. Steel is the most important of all manufactured

products, and the development of special grades is largely responsible for the enormous amount of building construction, the great extension of railroads, and the great multiplication and expansion of industry that has occurred in recent years. Steel is a finished product of which iron is the raw material. The ores of iron are red hematite (Fe, O,), brown hematite, the limonite of the mineralogist (2 Fe, O, and 3 H 2O), magnetite (Fe, O,), and siderite (Fe Co), these being mixed with more or less silica, clay, etc., besides containing a small percentage of manganese, phosphorus and sulphur.

To extract the metallic content from any ore, it is necessary to get rid of the impurities. With all metals this is done by melting the ore by intense heat and adding what is known to the metallurgist as a flux. A flux is any mineral, usually lime, which

19 65

FIG. 69. The Bessemer Converter.

unites with the impurities of the ore to form a liquid slag which floats upon the molten metal. The metal can then be drawn off from the bottom of the furnace, but is still in a more or less impure state and needs to be refined. This is the case with iron. Crude iron is made in very large circular vertical blast furnaces (see fig. 68), which are lined with refractory fire brick. In the blast furnace ore and limestone, which is used as a flux, together with the coke necessary for providing the intense heat, are raised to the top of the furnace by a hoist (A) and discharged into the hopper (B) and these materials fall into the hopper (D) at the top of the furnace by lowering the bell (C). When the bell (E) is lowered the materials are dropped into the furnace. The two bells and hoppers are provided to prevent the escape of large volumes of gas from the top of the furnace. In order to provide sufficient air for combustion of the coke enormous volumes heated

to 1,100 to 1,500 degrees F. are blown through a set of pipes called "tuyeres" near the bottom of the furnace at a pressure of 12 to 15 pounds per square inch. The burning coke melts the charge, producing intense local heat. About three-quarters of a pound of coke is used per pound of pig iron made. The air blast coming through the tuyeres is heated by passing it through

"stoves" which are large cylindrical structures filled with a checker-work of fire brick. One blast furnace usually has three or four "stoves." After the chemical action is completed within the furnace the crude iron is drawn off into moulds called "pigs." Pig iron, however, contains impurities which must be burned away before a good quality of steel is produced. Of the impurities found in iron, graphite is unique, inasmuch as it is rarely found in other metals. It is present in the form of flakes or thin