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Successful under-water coal storage
Aug., 1916.]
U. S. BUREAU OF STANDARDS NOTES.
259
fundamental units or in the constants in the defining equations. These are the C.G.S., the so-called" practical," and the Heaviside units. The units used in practice are the " international" units, so called by the international congresses which defined them. They represent the electromagnetic units for practical purposes, and the fundamental international units were so defined as to be equal to the corresponding electromagnetic units as closely as known at the time of definition. The slight differences which have been found by absolute measurements are tabulated in the circular, for the convenience of the occasional investigator who may desire to convert from one system to the other. The system of concrete standards by which the electric units are now maintained is the result of an evolution extending over 70 years. The units are maintained by the national standardizing laboratories in accordance with the decisions of the I9o8 International Conference at London. The circular gives the definitions of the units and detailed information regarding the units and standards of resistance, current, electromotive force, quantity of electricity, capacity, inductance, power and energy, resistivity, and the magnetic quantities. In an appendix, conversion factors for the above units are given, both for units of different systems and for the international units as maintained at different times and places. The laws on electric units in different countries are given. A selected bibliography of the literature pertaining to electric and magnetic units and standards is included. Successful Under-water Coal Storage. J.D. WARDLE. (E~ectric Railway Journcfl, vol. xlvii, No. 26, June 24, I916.)--The Iowa Railway and Light Company, which operates about fifty mi|es of interurban line and has more than 35o miles of high-tension distribution, serving lighting and power consumers in central Iowa, has recently put into service a large under-water coal storage. Iowa coal when piled ignites itself readily, and it is, therefore, necessary to store it in a flooded pit. The coal is reclaimed from the pit with a IS-ton electric locomotive crane. With a consumption of coal of 250 tons a day, it was formerly necessary to carry 5ooo or 60oo tons in reserve in cars at a per diem charge of 45 cents. With underwater storage the number of reserve cars has been reduced to ten and the daily charge from $45 to $4.5o.
U. S. BUREAU OF STANDARDS NOTES.
259
fundamental units or in the constants in the defining equations. These are the C.G.S., the so-called" practical," and the Heaviside units. The units used in practice are the " international" units, so called by the international congresses which defined them. They represent the electromagnetic units for practical purposes, and the fundamental international units were so defined as to be equal to the corresponding electromagnetic units as closely as known at the time of definition. The slight differences which have been found by absolute measurements are tabulated in the circular, for the convenience of the occasional investigator who may desire to convert from one system to the other. The system of concrete standards by which the electric units are now maintained is the result of an evolution extending over 70 years. The units are maintained by the national standardizing laboratories in accordance with the decisions of the I9o8 International Conference at London. The circular gives the definitions of the units and detailed information regarding the units and standards of resistance, current, electromotive force, quantity of electricity, capacity, inductance, power and energy, resistivity, and the magnetic quantities. In an appendix, conversion factors for the above units are given, both for units of different systems and for the international units as maintained at different times and places. The laws on electric units in different countries are given. A selected bibliography of the literature pertaining to electric and magnetic units and standards is included. Successful Under-water Coal Storage. J.D. WARDLE. (E~ectric Railway Journcfl, vol. xlvii, No. 26, June 24, I916.)--The Iowa Railway and Light Company, which operates about fifty mi|es of interurban line and has more than 35o miles of high-tension distribution, serving lighting and power consumers in central Iowa, has recently put into service a large under-water coal storage. Iowa coal when piled ignites itself readily, and it is, therefore, necessary to store it in a flooded pit. The coal is reclaimed from the pit with a IS-ton electric locomotive crane. With a consumption of coal of 250 tons a day, it was formerly necessary to carry 5ooo or 60oo tons in reserve in cars at a per diem charge of 45 cents. With underwater storage the number of reserve cars has been reduced to ten and the daily charge from $45 to $4.5o.