The Metric System is a decimal system of measures and weights, based on the meter as its unit, which originated in France during the last decade of the eighteenth century, and has since been adopted by the greater number of States in Europe and America. In the United States its use was authorized in 1866 by Act of Congress. The length of the meter was intended to be one ten-millionth part of the distance from the equator to either pole, measured at the level of the sea, but it is in reality a trifle less. All other units for measuring and weighing are derived from it, and the higher or lower denominations of the same kind of measure are obtained by multiplying or dividing its unit by tens, and prefixing to its name the Greek numerals, deka 10, hekto 100, kilo 1000, or myria 10000, for the higher denominations, and the Latin numerals, deci 1/10, centi 1/100, or milli 1/1000, for the lower. The unit of weight, called the gram, is theoretically the weight in vacuo of a cubic centimeter of distilled water at the temperature of maximum density assumed to be 4° C. or 39° 1 Fe.

Including the meter and gram, five units have been adopted in the metric system, viz.:—

For practical purposes the following are commonly used as units, viz.:—

Metric Equivalents of English Measures and Weights.

LONG MEASURE.

SQUARE MEASURE.

LIQUID MEASURE.

DRY MEASURE.

AVOIRDUPOIS WEIGHT.

TROY WEIGHT.

Table for Reducing Pounds and Ounces to Kilograms.