THE METRIC SYSTEM The need for a single worldwide coordinated measurement system was recognized over 300 years ago. Gabriel Mouton,Vicar of St.Paul's Church in Lyons and an astronomer,proposed in 1670 a comprehensive decimal measurement system based on the length of one minute of arc of a great circle of the Earth.Mouton also proposed the swing length of a pendulum with a frequency of one beat per second as the unit of length.A pendulum with this beat would have been fairly easily reproducible,thus facilitating the widespread distribution of uniform standards.Other proposals were made,but more than a century elapsed before any action was taken.(Please see footnote regarding this reference to Gabriel Mouton's proposed swing length of a pendulum with frequency of one beat per second.) In 1790,in the midst of the French Revolution,the National Assembly of France requested the French Academy of Sciences to "deduce an invariable standard for all the measures and all the weights." The Commission appointed by the Academy created a system that was,at once,simple and scientific The unit of length was to be a portion of the Earth's circumference.Measures for capacity (volume)and mass were to be derived from the unit of length,thus relating the basic units of the system to each other and to nature.Furthermore,larger and smaller multiples of each unit were to be created by multiplying or dividing the basic units by 10 and its powers.This feature provided a great convenience to users of the system,by eliminating the need for such calculations as dividing by 16(to convert ounces to pounds) or by 12(to convert inches to feet).Similar calculations in the metric system could be performed simply by shifting the decimal point Thus,the metric system is a "base-10"or "decimal"system. The Commission assigned the name metre-meter-to the unit of length.This name was derived from the Greek word metron,meaning "a measure."The physical standard representing the meter was to be constructed so that it would equal one ten-millionth of the distance from the North Pole to the equator along the meridian running near Dunkirk in France and Barcelona in Spain. The initial metric unit of mass,the "gram,"was defined as the mass of one cubic centimeter(a cube that is 0.01 meter on each side)of water at its temperature of maximum density.The cubic decimeter (a cube 0.1 meter on each side)was chosen as the unit for capacity.The fluid volume measurement for the cubic decimeter was given the name "liter." Although the metric system was not accepted with enthusiasm at first,adoption by other nations occurred steadily after France made its use compulsory in 1840.The standardized structure and decimal features of the metric system made it well suited for scientific and engineering work Consequently,it is not surprising that the rapid spread of the system coincided with an age of rapid technological development.In the United States,by Act of Congress in 1866,it became"lawful throughout the United States of America to employ the weights and measures of the metric system in all contracts,dealings or court proceedings." 3THE METRIC SYSTEM The need for a single worldwide coordinated measurement system was recognized over 300 years ago. Gabriel Mouton, Vicar of St. Paul's Church in Lyons and an astronomer, proposed in 1670 a comprehensive decimal measurement system based on the length of one minute of arc of a great circle of the Earth. Mouton also proposed the swing length of a pendulum with a frequency of one beat per second as the unit of length. A pendulum with this beat would have been fairly easily reproducible, thus facilitating the widespread distribution of uniform standards. Other proposals were made, but more than a century elapsed before any action was taken. (Please see footnote regarding this reference to Gabriel Mouton's proposed swing length of a pendulum with frequency of one beat per second.) In 1790, in the midst of the French Revolution, the National Assembly of France requested the French Academy of Sciences to "deduce an invariable standard for all the measures and all the weights." The Commission appointed by the Academy created a system that was, at once, simple and scientific. The unit of length was to be a portion of the Earth's circumference. Measures for capacity (volume) and mass were to be derived from the unit of length, thus relating the basic units of the system to each other and to nature. Furthermore, larger and smaller multiples of each unit were to be created by multiplying or dividing the basic units by 10 and its powers. This feature provided a great convenience to users of the system, by eliminating the need for such calculations as dividing by 16 (to convert ounces to pounds) or by 12 (to convert inches to feet). Similar calculations in the metric system could be performed simply by shifting the decimal point Thus, the metric system is a "base-10" or "decimal" system. The Commission assigned the name metre - meter - to the unit of length. This name was derived from the Greek word metron, meaning "a measure." The physical standard representing the meter was to be constructed so that it would equal one ten-millionth of the distance from the North Pole to the equator along the meridian running near Dunkirk in France and Barcelona in Spain. The initial metric unit of mass, the "gram," was defined as the mass of one cubic centimeter (a cube that is 0.01 meter on each side) of water at its temperature of maximum density. The cubic decimeter (a cube 0. 1 meter on each side) was chosen as the unit for capacity. The fluid volume measurement for the cubic decimeter was given the name "liter." Although the metric system was not accepted with enthusiasm at first, adoption by other nations occurred steadily after France made its use compulsory in 1840. The standardized structure and decimal features of the metric system made it well suited for scientific and engineering work. Consequently, it is not surprising that the rapid spread of the system coincided with an age of rapid technological development. In the United States, by Act of Congress in 1866, it became “lawful throughout the United States of America to employ the weights and measures of the metric system in all contracts, dealings or court proceedings.” 3