What was used in determining the original length of a meter?

Answer 1

The origins of the meter go back to at least the 18th century. At that time, there were two competing approaches to the definition of a standard unit of length. Some suggested defining the meter as the length of a pendulum having a half-period of one second; others suggested defining the meter as one ten-millionth of the length of the earth's meridian along a quadrant (one fourth the circumference of the earth). In 1791, soon after the French Revolution, the French Academy of Sciences chose the meridian definition over the pendulum definition because the force of gravity varies slightly over the surface of the earth, affecting the period of the pendulum.

Answer 2

The original length of a meter was based on one ten-millionth of the distance from the Earth's equator to the North Pole, as measured along the meridian passing through Paris. This measurement was established during the French Revolution in the late 18th century.