Outlines of the Evolution of Weights and Measures and the Metric System

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Macmillan, 1906 - 304 Seiten
 

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Seite 10 - And Abraham hearkened unto Ephron; and Abraham weighed to Ephron the silver, which he had named in the audience of the sons of Heth, four hundred shekels of silver, current money with the merchant.
Seite 113 - THE United States in Congress assembled shall also have the sole and exclusive right and power of regulating the alloy and value of coin struck by their own authority, or by that of thev respective States — fixing the standard of weights and measures throughout the United States...
Seite 213 - ... As a unit of electromotive force, the international volt, which is the electromotive force that, steadily applied to a conductor whose resistance is one international ohm, will produce a current of one international ampere, and which is represented sufficiently well for practical use by \\\% of the electromotive force between the poles or electrodes of the voltaic cell known as Clark's cell, at a temperature of 15° C., and prepared in the manner described in the accompanying specification...
Seite 213 - As a unit of work, the joule, which is equal to 10' units of work in the CGS system, and which is represented sufficiently well for practical use by the energy expended in one second by an international ampere in an international ohm. . As a unit of power, the watt, which is equal to 10...
Seite 216 - The result will be the time-average of the current, if during the interval the current has varied. In determining by this method the constant of an instrument the current should be kept as nearly constant as possible, and the readings of the instrument observed at frequent intervals of time. These observations give a curve from which the reading corresponding to the mean current (time-average of the current) can be found. The current, as calculated by the voltameter, corresponds to this reading.
Seite 213 - 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.
Seite 213 - As a unit of resistance, the international ohm, which is based upon the ohm, equal to 109 units of resistance of the Centimeter-Gramme-Second System of electro-magnetic 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 grammes in mass, of a constant cross-sectional area, and of the length of 106-3 centimeters.
Seite 117 - A uniformity in the weights and measures of the country is among the important objects submitted to you by the constitution, and, if it can be derived from a standard at once invariable and universal, must be no less honorable to the public councils, than conducive to the public convenience.
Seite 214 - In employing the silver voltameter to measure currents of about one ampere, the following arrangements should be adopted : The kathode on which the silver is to be deposited should take the form of a platinum bowl, not less than 10 centimetres in diameter and from 4 to 5 centimetres in depth.
Seite 123 - States to the provisions of this act, the brass troy -pound weight procured by the minister of the United States at London, in the year eighteen hundred and twenty-seven, for the use of the mint, and now in the custody of the mint at Philadelphia, shall be the standard troy pound of the mint of the United States, conformably to which the coinage thereof shall be regulated.

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