Weights and measures are among the most fundamental tools used by men. Primitive cultures required measures for daily tasks, such as constructing dwellings, making clothing and bartering. Local customs often determined systems of measurement in the early days. Length, for example, was measured by the arm, hand or fingers, and weight was determined by the number of seeds or grains in a jar. The obvious problem with this arrangement was not all arms were the same length; nor were grains of barley or wheat the same size. As a result, intellectuals of the 17th century began to realize that a standard system of measurement was needed.
The metric system was created more than 100 years after the first standard decimal-based measurement systems were proposed. In 1790, in the midst of the French Revolution, the National Assembly of France requested that the French Academy of Sciences develop a standard system of weights and measures. The metric system was designed for use by all people -- from the simplest worker to physicists and astronomers. It was officially adopted by the French government in 1795. Although the metric system was temporarily suspended by Napoleon in 1812, it was reinstated as the official French system of weights and measures in 1840.
In 1960, the General Conference of Weights and Measures adopted a revision of the metric system. The new system is officially named the Systeme International d'Unites (SI). The new, simplified system designates seven official units: meter (length), kilogram (mass), kelvin (temperature), second (time), mole (amount of substance), ampere (electric current) and candela (luminous intensity). The SI is still commonly called the metric system, but that name is technically incorrect.
In 1790, the United States' first Secretary of State, Thomas Jefferson, proposed his own decimal-based system of weights and measures to replace the English system of measurements in use at the time. Jefferson's proposed system failed to pass the U.S. congress by one vote, and the English system is still in use today. Though the U.S. still uses a system similar to the one used by the colonists 250 years ago, many American businesses have adopted the SI to deal with the international business community.