Metric System

a scientific system of weights and measures. In 1799 an international commission representing ten countries met in Paris to adopt a system of measurements that should be based on some exact unit and be acceptable to all nations. The unit thus settled upon is the ten-millionth part of the distance from the equator to the pole. It is 39.37 inches, a little more than a yard in length. All other units are based on this metre. For distances, the unit of distance is the kilometer, equivalent to 1,000 metres, or over three-fifths of a mile. The unit of area is the are, or 100 square metres. The unit of capacity is the litre, a cube one edge of which is one-tenth of a metre in length. It is about half way between the quart of dry measure and the liquid quart.

The unit of weight is the gram. It is the weight of a cube of pure water at its greatest density, whose edge is one-hundredth of a metre. A silver dollar weighs twenty-five grams; a nickel five-cent piece weighs five grams. The kilogram of 1,000 grams is equivalent to two and one-half pounds. The metric system is decimal throughout. Multiples of these units, that is to say, larger units, are named by the use of the Greek prefixes deka, hecto, kilo, and myria, meaning 10, 100, 1000, and 10,000 respectively. The decimal parts of the units are named by using the Latin prefixes, deci, centi, and milli, meaning 1/10, 1/100, 1/1000 respectively. A dekametre is ten metres; a decimetre is one-tenth of a metre, etc.

Although the names have not been retained in all cases, the metric system has been adopted by Mexico, the countries of South America, and by all European nations except the Russian and the British. In these countries cloth is sold by the metre; railroad distances are stated in kilometres; milk, kerosene, and wines are sold by the litre; potatoes are measured by the hectolitre; land is sold by the hectare; the druggist and the postmaster reckon by grams and the grocer weighs out his sugar, coffee, and tea in kilograms. The system is learned readily. Computations are made with little labor. It is understood by educated people of all nations. For these reasons the system has been adopted by the scientists of all English-speaking nations.

TABLE OF ENGLISH AND METRIC EQUIVALENTS.

See Foot; Yard; Avoirdupois; Troy Weight