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absolute accuracy acid adopted alternating current ampere anode black body bridge c. g. s. units calibration capacity cathode cent centimeters circuit Clark cell clinical thermometers column comparison condenser Congress constant correction coulometer crystals defined deposit determined effect electrical units electrodes electromotive force energy equal equation error experiments frequency galvanometer give given glass grams harmonic heated hence hydrogen incandescent inductive coil instrument International Bureau lamp light magnetic mean mercurous sulphate mercury metallic meter method mirrors observations obtained optical pyrometer photometric Phys platinum porous cup potential practical pressure pure pyrom pyrometer radiation rheostat secondary shown silver nitrate silver voltameter solution spark spectra spectrum Table temperature thermometers tion tube unit of resistance vapor variations varied voltage volts wattmeter wave length weights and measures Weston cell Wien's Wien's law wire zinc sulphate
Page 61 - The unit of current shall be what is known as the international ampere, which is onetenth of the unit of current of the centimeter-gramsecond system of electro-magnetic units, and is the practical equivalent of the unvarying current, which, when passed through a solution of nitrate of silver in water in accordance with standard specifications, deposits silver at the rate of one thousand one hundred and eighteen millionths of a gram per second.
Page 46 - Ampere, which is one-tenth of the unit of current of the CGS system of electromagnetic units and which is represented sufficiently well for practical use by the unvarying current which, when passed through a solution of nitrate of silver in water, in accordance with a certain specification, deposits silver at the rate of 0.001118 of a gramme per second.
Page 61 - As a unit of resistance, the international ohm, which is based upon the ohm equal to 10" units of resistance of the CGS system of electromagnetic units, and is represented by the resistance offered to an unvarying electric current by a column of mercury at the temperature of melting ice, 14.4521 grams in mass, of a constant cross-sectional area and of the length of 106.3 centimetres.
Page 372 - Custom-Houses, and for other purposes, to be delivered to the governor of each state in the Union, or such person as he may appoint, for the use of the states respectively, to the end that a uniform standard of weights and measures may be established throughout the United States.
Page 47 - The liquid should consist of a neutral solution of pure silver nitrate, containing about 15 parts by weight of the nitrate to 85 parts of water. The resistance of the voltameter changes somewhat as the current passes. To prevent these changes having too great an effect on the current, some resistance besides that of the voltameter should be inserted in the circuit.
Page 68 - ... distilled water with nearly twice its weight of crystals of pure zinc sulphate, and adding zinc oxide in the proportion of about 2 per cent, by weight of the zinc sulphate crystals to neutralise any free acid. The crystals should be dissolved with the aid of gentle heat, but the temperature to which the solution is raised should not exceed 30° C.
Page 74 - The International Ohm is the unit of resistance and is defined as the resistance offered to an unvarying current by a column of mercury at the temperature of melting ice, 14.4521 grams in mass, 106.300 cm.
Page 61 - ... international farad, which is the capacity of a condenser charged to a potential of one international volt by one international coulomb of electricity.
Page 61 - As a unit of electro-motive force, the international volt, " which is the electro-motive force that, steadily applied to a " conductor whose resistance is one international ohm, will '• produce a current of one international ampere...
Page 70 - In the following specification the term silver voltameter means the arrangement of apparatus by means of which an electric current is passed through a solution of nitrate of silver in water. The silver voltameter measures the total electrical quantity which has passed during the time of the experiment, and by noting this time the time average of the current, or if the current has been kept constant, the current itself, can be deduced.