have thus chosen the middle ground, illustrated the reasoning on the typical thermodynamic cycles, and left it to the intelligence of the reader to realize that the actual engine cycles are intermediate between, and combinations of, the typical cycles, and hence are covered by the results of the typical cycles. Professor Lucke's statement, that the temperature range has no effect on the efficiency of the thermodynamic cycle, obviously is wrong. If his idea of gas-engine design is to put as much heat into the cylinder as possible, and see what power he gets out of it, and he does not care to know what the temperature is; this obviously does not prove that the temperature is immaterial. In general, an efficient designing engineer endeavors to know not only what is put into, and what comes out of an apparatus, but still more, what takes place in the apparatus. The rapid advance of electrical engineering is to a large extent due to the fact that the designing electrical engineer was not satisfied merely to put as much mechanical power into the machine as possible, and measure whatever electrical output he got, but has carefully studied the internal reactions of the apparatus, and thereby was enabled intelligently to choose and predetermine the actions, with the result that the waste of power in electrical apparatus has been reduced to a negligible quantity. However, Professor Lucke's method of gas-engine design, by putting as much heat as possible into the cylinder, is merely a repetition, in different words, of the assumption which I made in my paper for the air cycles. These cycles I consider for the conditions of maximum output, where the greatest amount of heat is put into the cylinder, which still increases the output. The claim made by Professor Lucke and Mr. Longwell, that the assumptions made in my paper are arbitrary, and by a different set of equally justified assumptions any other conclusion can be reached, is wrong; the assumptions made in my paper are not arbitrary, but, as proper in such investigations, I have chosen the conditions most favorable for each case. That is, where the efficiency or output increases with the temperature, I have chosen the highest temperature; where the efficiency or output increases with the pressure, I have chosen. the highest pressure permissible by reasonably conservative design. The only feasible variations of the assumptions thus are minor changes: some engineers may consider 24 atmospheres too high, and prefer 20 atmospheres as a more conservative limit, while another engineer may be willing to allow pressures up to 30 atmospheres. As I have stated in my paper, however, the results and the conclusions, are not appreciably changed by any reasonable change of my assumptions. Incidentally, Mr. Longwell is mistaken in his statement that equality of the two intermediate temperatures of the air cycle. fulfils the conditions of maximum output per unit weight of air. This happens to be the case for the two cycles specifically discussed in my paper, but not in general. For instance, for the air cycle of constant pressure admission and constant volume exhaust, in the conditions of maximum output---which is the assumption of my paper-the two intermediate temperatures are not equal. His statement that the efficiency of the isobaric cycle of saturated steam is that of the Carnot air cycle between the same temperature limits, is not quite correct either, but the efficiency of the steam cycle is slightly lower, though the difference is usually small. My paper discusses the economy of the production of electric power from nature's stores of energy to the switchboard. If one corporation develops the water-power, another one uses it by buying the water of the former. This obviously does not change the cost of development etc., and you do not get waterpower without cost of development, as Mr. Longwell seems to think, if you let somebody else develop the water-power, and pay him for the cost of development in the price of water bought of him. The economic considerations from the station switchboard to the light radiated from the customer's lamps, are equally important, as Mr. Longwell states, but they are not the subject of my paper. I am sorry that Mr. Longwell thinks the kilojoule a new unit: the kilojoule, or kilowatt-second, is, and has been for some decades, the international unit of energy, used throughout the world, not only by the electrical engineers, but also by other engineers, such chemists as Ostwald, and others, with the exception of that rapidly dwindling group of mechanical engineers in the two English speaking countries, who still prefer to measure distances by what in the earlier middle ages was considered the proper length of a king's foot, and to measure temperatures by a scale using as zero the lowest winter temperature of Northern Germany, and as 100 degrees an erroneous measurement of blood heat (Fahrenheit). While the two English speaking nations have not yet reached the courage of completely freeing themselves of the curse of the ancient English system (socalled because all the other civilized nations have long ago discarded it), with its seven or more incompatible units of length* and other curios, I would not impose such a system on the American Institute of Electrical Engineers which already years ago has gone on record as endorsing the metric system, by a ballot vote of over 90 per cent majority. It is true, that in the English system, when expressing the energy of fuel in British thermal units, the output of the boilers in pounds of steam per hour, the indicated energy of the engine in foot-pounds, and the output at the switchboard in kilojoules, the numerical values are not so disturbing to the self-satisfaction of the engineer as when throughout the entire transformation, the energy is expressed by the same units, and the inefficiency of the performance thereby shown in all its nakedness. * Foot, mile, chain, rod, fathom, knot, yard, etc. But, whether such a hiding of the inefficiency is to the advantage of the art, is questionable. In regard to Mr. Longwell's objections to my statement that electric energy is a secondary form of energy, I shall be glad to withdraw this statement, as soon as Mr. Longwell will have succeeded in harnessing the thunder cloud, and in lighting the cities from nature's stores of electricity, from lightning, or from the earth currents, or whatever other of nature's stores of electricity he has in mind for industrial use. American Institute of Electrical Engineers, Copyright 1909. By A. I. E. E. THE INDUSTRIAL APPLICATION OF THE ELECTRIC MOTOR, AS ILLUSTRATED IN THE GARY PLANT OF THE INDIANA STEEL COMPANY* BY B. R. SHOVER Introduction and historical. Twenty years ago electricity, except for lighting purposes, was virtually unknown to the iron. and steel industries, while to-day in all the steel works in this country it is used as a motive power for most of the auxiliary machinery, from the ore docks to the loading beds. The electric drive is utilized in ore unloaders, ore bridges, car dumpers, bin-filling cars, scale larries, blast-furnace skips, hot-metal mixers, electric cranes of all sizes and descriptions, open-hearth charging machines, ingot buggies, gas producers, roller tables, lifting tables, transfers, hot-bed apparatus-in short, a multitude of machines too numerous to mention here. This development has been such that it would probably be no exaggeration to say that the steel industry in this country would never have reached its present proportions without the use of electric motors. As a further gauge of progress, it is significant that the larger electric manufacturing companies have been forced to establish special departments to look after the business of the steel industries. Development of the direct-current motor. The first application of electric power to the steel-mill industry was by means of the * The magnitude of the work in this plant has been such that without the hearty coöperation of the staffs of all the electrical manufacturing companies (practically all of whom have contributed to the work) it would have been impossible to obtain the results herein outlined. The author is, therefore, glad of this opportunity publicly to acknowledge the valuable assistance which they have given him and his company in this work. 101 |