The metric system of measurement is French in origin and is largely used in Continental Europe. It is the system used by nearly all scientific workers and is finding more and more favor in this country. In this system the unit of length is the centimeter, which is one-hundredth part of a meter. The meter is one ten-millionth part of the distance on the earth's surface from the equator to the pole. It is defined in the United States and France as the distance on certain bars in Washington and Paris which are kept at the temperature of melting ice. The unit of weight is the gram, which is equal to about onethirtieth of an ounce. The unit of volume is the liter which is a little larger than a quart. The gram is the weight of one cubic centimeter of pure distilled water at a temperature of 39.2° Fahrenheit; the kilogram is the weight of one liter of water; the metric ton is the weight of one cubic meter of water.
The principal advantage of the metric system consists in the use of decimal subdivisions and ease in calculations. The principle of the metric system is sound, but since there is no exact equivalent between the metric and English systems it is difficult to use the former for practical purposes where machines and formulas have been made according to the English system.