History of Units and Measurements

“Weights and measures may be ranked among the necessaries of life to every individual of human society. They enter into the economical arrangements and daily concerns of every family. They are necessary to every occupation of human industry; to the distribution and security of every species of property; to every transaction of trade and commerce; to the labors of the husbandman; to the ingenuity of the artificer; to the studies of the philosopher; to the researches of the antiquarian; to the navigation of the mariner, and the marches of the soldier; to all the exchanges of peace, and all the operations of war. The knowledge of them, as in established use, is among the first elements of education, and is often learned by those who learn nothing else, not even to read and write. This knowledge is riveted in the memory by the habitual application of it to the employments of men throughout life.”

-JOHN QUINCY ADAMS (Congress Report, 1821)

Measuring system evolved with the human civilization and became part of day-to-day activities. Even though varied systems were followed, the purpose remained the same. At early stages of civilization, man integrated his body parts and nature as measuring instruments. Some examples are below.

• Length was measured using arms and limbs.
• Time was measured by the position of sun, moon and other heavenly bodies.
• Seeds and stones were used to quantify the materials.
• To weigh small valuable gems and precious stones, they used a small bean called carob, which was the origin of the word carat.

As the civilization grew, global communication and international trade led to standardization of these measuring systems.

Measurement Standard in World History

Mankind made a progress in standardizing measurement for around 700 years. Some of them are stated below.

• The Arabs established a small weight standard for gold, silver and precious stones which very often were a part of trade or barter deals. The Babylonians used different stones for weighing different commodities. The Egyptians and the Greeks used a wheat seed as the smallest unit of weight.
• The romans marched and kept track of the distance they travelled by their counting paces.
• King Edward I of England ordered an iron measuring stick called as iron ulna, to serve as a standard yardstick for the entire kingdom. He also announced that the foot measure should be one-third the length of the yard and the inch should be one thirty-sixth.
• King Edward II returned back to the ancient seed concept and decreed that three round and dry barleycorns make an inch.
• In 1962, Sir Isaac Newton presented Newton’s Rings to the world which eventually led to the discovery of measurement using light rays.
• In 1793, the French government adopted metric system based on meter. The metric system also has volume, liquid capacity and weight measures.
• In the meantime, England was also working on scientifically to accurately determine yard using pendulum. Galileo found that the time duration of the pendulum to complete a swing depends upon the length of the pendulum itself.
• In 1824, the English parliament legalized a standard yard, which had been made in 1760. The same act also made the provision that this yard can be replaced using pendulum method, if lost or destroyed.
• A few years later, both the English yard and French meter standards were brought to the United States.
• By 1900, many nations including continental Europe and most of South America had officially accepted the metric system.
• In 1960, SI system (International System of Units) was established due to the requirement of accuracy and simplicity.
• Advancements were made in SI system in the years of 1964, 1967, 1968, 1971, 1975, 1979, 1983, 1991 and 1995.

The conversion from traditional measurement systems to the metric system happened by three main ways, stated as follows.

1. Big bang route, which was used by India in the 1960s and followed by Australia, New Zealand and several other nations.
2. In order to outlaw traditional units and progress units over time.
3. In order to redefine traditional units in metric terms.