Metre

The unit of measure in the “metric system” of weiglits and mcasures. It is a measure of iength, being the ten-millionth part of the distance from the equator to the north pole, and equivalent to 39.87 inches. From this unit all the other denominations of measure, aa well as of weight, are derived. ‘Me metric system was first adopted in France in 1795.

or METER. The ten-millionth part of a quadrant of a terrestrial meridian — from the equator to the north pole. Practically, the length of a platinum bar intended to be equal to one ten-millionth of the meridian which passes through Paris, and equivalent to 39.368 American inches. Metric system. A system for measuring length, capacity, surface, and weight, founded upon the metre as a unit. The act of July 28, 1866, re-enacted in Rev. St. §§ 3669-70 (where tables of equivalents are given), authorized the use of the system, and directed that standards be furnished to each of the States.

or METER. A unit of measurement, of French contrivance, introduced about the commencement of the present century, as the basis of an improved system of weights and measures. In theory, the metre is the tenmillionth part of a quadrant of a terrestrial meridian. The motive for the selection of such a unit was the desire to secure a standard which should be superior to all change; as unalterable as the dimensions of the earth; one which could never, by any complication of circumstances, be permanently lost. But the terrestrial meridians are not perfectly equal; for the determination of the standard to be employed a particular meridian had therefore to be selected, and from the most careful measurements of this which could be made, an actual standard unit of length was adopted. Practically, therefore, the metre is the length of a certain platinum bar, originally constructed to be closely equal to one ten-m Ulionth part of the terrestrial meridional quadrant passing through Paris; this being the one selected for the purpose, and its length having been determined by an elaborate measui'ement of nearly oneninth part (9° 40') of that quadrant. The precision of its correspondence with any aliquot part of a great circle has been contested on the basis of improvements m the art of terrestrial measurement; but doubts of this kind have not led to any change in the unit. Its equivalent is 39.368 American, or 39.370 English, inches. Prom this unit, as a basis, all the denominations of weights and measures employed in the metric system are deduced. Linear measures are the multiples or aliquot parts of the metre. Measures of surface and of solid capacity are formed by employing linear measures in two or three directions, on the same principle as the superficial or solid foot is measured by the linear foot. For capacity, a, cube of water, measuring one decimetre in each dimension, is taken as the unit, multiples or aliquot parts of this give the various measures of weight. And specific gravities are deduced by calling that of water the unit. Metric system. A system of measurement of length, capacity, surface, or weight, founded upon the metre (g. v.) as a unit, and recommended for general adoption and common use among civilized nations, on the grounds of its superior simplicity and accuracy, and of the advantage of employing a common system among different countries. The employment of the metric system throughout the United States is authorized, not made obligatory, by the act of congress of 28th July, 1866, re-enacted in Rev. Stat. §§ 3569, 3570, where tables of equivalents are given. It was similarly authorized in Great Britain in 1864. The act of congress of 1866 provided that standards of weight and measure conformed to the metric system should be prepared at the bureau of weights and measures in Washington, and furnished to the executive authorities of all the states; and authorized employment of metric weights and balances in post-oflaces, for weighing letters.