Metric System
The metric system of weights and measures was first adopted in France, and by Act of Congress was authorized to be used in this country 1866. It is a decimal system, and the units of length, superficies, solidity, and weight are all correlated, two data only being used--the metre, and the weight of a cube of water the side of which is the hundredth part of a metre. Upon the metre are based the following primary units: the square metre, the arc, the cubic metre or stere, the litre, and the gram. The square metre is the unit of measure for small surfaces. The arc is the unit of land measure, and is a square whose side is 10 metres in 1, or 100 square metres. The cubic metre or stere is the unit of volume, and is a cube whose edge is one metre in 1. The litre is the unit of capacity; this is the capacity of a cube whose edge is 1/10 of a metre in 1. The gram is the unit of weight, and is the weight of distilled water contained in a cube whose edge is the 1/100 part of a metre.
From these primary units the higher and lower orders of units are derived decimally. See METRE.