ELECTRICAL MANUFACTURING INDUSTRY. The conditions as to the elec trical manufacturing industries in the United States are fairly well revealed in the sta tistics of the Bureau of the United States Census for 1914, giving the latest authentic figures available, although these can be supplemented by later data in various ways that bring the information up to 1917 and that illustrate the swift and enormous expansion of the various electrical arts and applications. Electrical applications divide themselves into two large groups. One of these comprises the production of apparatus; and the other, many times larger, embraces the utilization of the apparatus chiefly through the agency of what are known as ((public utilities?' such as teleg raphy, telephony, electric lighting and power supply and electric traction. One group of in dustries manufactures operating materials; the other group manufactures °service?' In the United States, as sharply contrasted with Europe, these agencies are in the hands of private capital to an overwhelming degree, and the comparative figures of efficiency, economy and earning power are equally on the side of individual initiative and enterprise.
As to the production of electrical machinery, apparatus and supplies, the data are given here with for 1914, when the total output for 1121 establishments was placed at a value of $359, 412,676, against which may be placed the fact that in 1916, three concerns billed a total sales of not less than $305,000,000. The very lowest estimate for 1917 is $600,000,000 and in view of the enhanced cost of raw material it would not be surprising if it ran in excess of that amount. These figures are revelatory of many new con ditions governing the electrical arts, such as the change from steam engines to steam tur bines in the generation of electrical energy, the increased use of water power, the invasion of electricity into many new fields of supply, in dustrial, commercial and domestic; the greater use of the electric motor; the advance of elec tric heating; the supersession of the arc light by the larger incandescent; the complete con quest of the incandescent lighting field by the tungsten filament lamp; the irresistible intrusion of the electric locomotive, not only into steam railway terminals but Hit° the operation of long stretches of main line, where cheap water power is available for the generation of cur rent.
It will be noted that dynamos have greatly increased in size, and have fallen off in value, owing to this fact. In the early days of the elec tric-light and power industry it was customary to employ high speed, single valve automatic steam engines for driving belted generators, as the best regulation of speed could be obtained with engines of that type, for incandescent lighting. The steam economy of those engines was usually as low as a consumption of 40 pounds of steam per one horse power per hour. The mechanical efficiency was rarely as great as 85 per cent and the electrical efficiency of the generators was rarely 75 per cent. Corliss type engines were used for arc light circuits where the load was uniform and close regulation was not so essential. Their economy rarely exceeded 30 pounds of water per one horse power. For incandescent lighting there was an average con sumption of at least pounds of coal per kilowatt hour and for arc lighting 8 pounds of coal per kilowatt hour. This compares with the present Interborough Rapid Transit 50,000 kilowatt steam turbo generators requiring as little as one and one-half pounds of coal per kilowatt hour; while it is understood that the Connell Creek station of the Detroit Edison Company has an economy even superior to that. There is a 60,000 k. v. a. triple steam turbine under construction for the Interborough sys tem, which will have an actual capacity of 70,000 k. v. a. and is expected to have an economy of 11 pounds of steam per kilowatt hour. The increase in the size and economy of hydro-electric generating units is equally notable. The largest water turbines for elec trical service are the three single runner units installed in the plant of the Tallassee Power Company on the Yadkin River, North Carolina, with a guaranteed rating of 31,000 horse power under an effective head of 180 feet, and 27,000 horse power under 165 feet at 154 r. p. m. The turbine runner weighs 20,000 pounds, is a single piece of solid bronze and is probably the largest casting of its kind ever made.