A History of Measurement and Metrics

Going as far back in time as Noah's ark, the lack of a yardstick was not a serious drawback. Most measuring was done by one craftsman completing one job at a time, rather than assembling a number of articles piecemeal to be assembled later, it didn't make much difference how accurate the measuring sticks were or even how long they were. Generally, it doesn't make much difference how long is a mile, yard or inch or how heavy is a pound or ounce. What is really important is that everyone means the same thing when referring to each unit of measurement. Measurements must be standard to mean the same thing to everyone.

The cubit of Noah's time was the length of a man's forearm or the distance from the tip of the elbow to the end of his middle finger. Many times this was useful, because it was readily available, convenient, and couldn't be mislaid. However, it was not a positive fixed dimension or a standard.

While the cubit is no longer used as a unit of measurement, there are many customary standards that originated in about the same way. Our foot-rule started out as the length of a man's foot. So, in the early days of history, the foot varied in length, sometimes as much as 3 or 4 inches. Once the ancients started using arms and feet for measuring distance, it was only natural that they also thought of using fingers, hands, and legs. They also may have discovered that some surprising ratios existed in body measurements. What is now called an inch originally was the width of a man's thumb. It also was the length of the forefinger from the tip to the first joint. Twelve times that distance made a foot. Three times the length of the foot was the distance from the tip of a man's nose to the end of his outstretched arm. This distance very closely approximates what is called the yard. Two yards equaled a fathom which, thousands of years ago, was the distance across a man's outstretched arms. Half a yard was the 18-inch cubit, and half a cubit was called a span, which was the distance across the hand from the tip of the thumb to the tip of the little finger when the fingers were spread out as far as possible. A hand was half a span.

For thousands of years, this was the way people measured comparatively short distances. Each succeeding civilization added to mankind's knowledge, building an accumulation of measuring standards and techniques. Some contributed weight measures. Others showed us how to measure time. Still, others gave us methods for surveying big areas of land and establishing boundaries.

In techniques for measuring weights, the Babylonians made important improvements upon the invention of the balance. Instead of just comparing the weights of two objects, they compared the weight of each object with a set of stones kept just for that purpose. In the ruins of their cities, archaeologists have found some of these stones finely shaped and polished. It is believed that these were the world's first weight standards.

The Babylonians used different stones for weighing different commodities. In modern English history, the same basis has been used for weight measurements. For the horseman, the "stone" weight was 14 pounds. In weighing wool the stone was 16 pounds. For the butcher and fishmonger, the stone was 8 pounds. The only legal stone weight in the imperial system was 14 pounds.

The Egyptians and the Greeks used a wheat seed as the smallest unit of weight, a standard that was very uniform and accurate for the times. The grain is still in limited use as a standard weight. However, wheat seeds are no longer actually put in the pan of the balance scale. Instead, a weight that is practically the same as that of an average grain of wheat is arbitrarily assigned to the grain. The Arabs established a small weight standard for gold, silver and precious stones which very often were a part of trade or barter deals. To weight the small valuable quantities, they used as a weight standard a small bean called a karob. This was the origin of the word carat which jewelers still use to express the weight of gems and precious metals.

In trading between tribes and nations, many of these methods for measuring weights and distances gradually became intermixed, particularly by the Romans who spread this knowledge throughout the known world at that time, also adding some standards of their own. As the Roman soldiers marched, they kept track of the distance they traveled by counting paces. A pace was the distance covered from the time one foot touched the ground until that same foot touched the ground again, or the length of a double step.

Seeking a Standard of Measurement in World History

When the Roman Empire passed into history about six hundred years after the time of Christ, Europe then drifted into the Dark Ages. For six or seven hundred years mankind generally made little progress with regard to standardizing measurement. Sometime after the Magna Charta was signed in the Thirteenth Century, King Edward I of England took a step forward. He ordered a permanent measuring stick made of iron to serve as a master standard yardstick for the entire kingdom. This master yardstick was called the "iron ulna", after the bone of the forearm, and it was standardized as the length of a yard, very close to the length of our present-day yard. King Edward realized that constancy and permanence were the key to any standard. He also decreed that the foot measure should be one-third the length of the yard, and the inch one thirty-sixth. King Edward II, in 1324, reverted back to the seed concept of the ancients and passed a statute that "three barleycorns, round and dry," make an inch. However, seeds, as well as fingers and feet, were no match for a world that soon was to emerge from the ignorance and unrefined practices of the Dark Ages.

In 1672, Sir Isaac Newton presented the world with new ideas on the nature of light and color. He had noticed that when two flat pieces of glass were pressed together, he could see circular bands of rainbow-like colors. These were called Newton's Rings. Actually, Newton had come upon a very precise method of measurement, but he didn't recognize it as such at the time. Later, other scientists were to build on Newton's seminal findings and establish a new branch of science called interferometry . Today, this method of using a ray of light as a measuring stick enables man to measure distances within millionths of an inch or a millimetre.

As the scientists were experimenting in their laboratories, practical tradesmen were making themselves permanent standards. In 1793, during Napoleon's time, the French government adopted a new system of standards called the metric system, based on what they called the metre. The metre was supposed to be one tenth-millionth part of the distance from the North Pole to the Equator when measured on a straight line running along the surface of the earth through Paris. With the metre now determined as the basis of the metric system, other linear units of the system were set up in decimal ratios with the metre. With this system, all units are in multiples of ten: ten decimetres in a metre, a hundred centimetres in a metre, and a thousand millimetres in a metre. In the other direction, there are ten metres in a dekametre, a hundred metres in a hectometre, and a thousand metres in a kilometre. Compared to the yardstick, the metre is just a little longer: 39.37 inches long.

The metric system also has volume, liquid capacity, and weight measures. The litre is the basic measure of liquid capacity. It corresponds roughly to a quart. For weight, the basic unit in the metric system was at first the gram; now it is the kilogram. The gram was a very small unit, for it takes a thousand grams -- or what is known as a kilogram -- to equal about 2.2 pounds.

The French government thought it had an infallible system of weights and measures that would be easy to use and would be embraced by everyone. But people were accustomed to thinking in terms of yards, inches, pounds and quarts. At first the new metre as a measure of length proved confusing. Most Frenchmen thought in the old familiar terms, doing some mental arithmetic to convert one quantity into another and, after nineteen years, Napoleon finally was forced to renounce the metric system. However, in 1837, France again went back to the metre, this time for good, hoping to make it universal throughout the world. Today almost all of the countries of the world use a modernized metric system called the SI metric system.

While France was evolving the metric system, England also was setting up a more scientifically accurate determination of the yard. Where the French relied on the assumed constancy of the earth's size as a basis for the permanency of their standards, the British turned to the measured beat of the pendulum. Galileo already had learned the secrets of a pendulum. He found that the length of time it took for a pendulum to complete a swing depended upon the length of the pendulum itself. The longer the pendulum, the slower it swung. He also found that a pendulum a little over 39 inches long would swing through its arc in exactly one second. Since a pendulum always behaves exactly the same way under the same conditions, here was another unchanging distance upon which to base a standard measurement.

In 1824, the English Parliament legalized a new standard yard which had been made in 1760. It was a brass bar containing a gold button near each end. A dot was engraved in each of these two buttons. These two dots were spaced exactly 1 yard apart. The same act that legalized this bar as the standard for England also made the provision that, in the event it was lost or destroyed, it should be replaced using the pendulum method to determine its length. A few years copies of both the English yard and the French metre standards were brought to the United States. The English system of measuring was almost universally adopted in the United States.

Measuring Systems in the United States

Since colonialists brought with them the measuring methods of their homeland, confusing and contradictory measuring systems came to America. For instance, the imperial gallon used in England did not come to America. The U.S. gallon is a smaller one, and was called the Queen Anne wine gallon by the British. Today this difference in size between the Imperial gallon and the U.S. gallon causes confusion when converting to the metric system.

The law of 1792, under the new Constitution of the United States, provided for fractional coinage and for the decimal system. The adoption of the decimal system for coins shows that the American leaders recognized the advantages of the simple decimal system. In 1795, France tried to convince the United States to use the metric system, but Congress did nothing. In 1821 John Quincy Adams wrote a comprehensive report for Congress based on a four-year investigation. His report dealt with the metric question and the modernization of our measurement system: An excerpt of the report follows:

"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."

This was the first U.S. metric study. Although three decades earlier, Thomas Jefferson also had written a report for the Congress on the need for modernization of weights and measures, the metric system was no more than a conception in this time, and his report was considered only an alternative not to be entertained seriously by the newly founded United States of America.

In spite of repeated requests in Congress, there was no legal length standard in the U.S. until 1832. More or less authentic copies of the British copies of the yard were used as length prototypes. In 1832, the Treasury Department decided to admit as a legal Yard the distance between the lines 27 and 63 of a certain bronze bar, 82 inches in length, bought in 1813 in England for the Federal Survey Department. When the British yard bar, which was destroyed in 1834, was replaced in 1855, a new bronze copy No. 11 was sent to the United States which became the legal American Yard Standard.

Even though progress was slow, there was an improvement in establishment of the metric standards which all the world recognized. Like the United Kingdom, the Americans found it necessary to define their customary measurements in terms of international metric standard. Our units of length, mass and volume are all stated in terms of the metric standards.

In 1863, the United States was represented at two important international congresses convened to consider matters of weights and measure. The International Statistical Congress in Berlin declared that uniformity in weights and measures was o the highest importance, particularly for international commerce. Recommendations made by the Postal Congress held at Paris resulted in the adoption of the metric system for international postal service.

Congress passed a Bill in 1866 which permitted use of the metric system of measurement in the United States. The value for the metre was given as: 1 metre = 39.37 inches or 1 yard = 0.914 401 829 metre. The metric prototype chosen was a metal bar known as the Committee Meter because it had been guaranteed to conform to the Metre des Archives by the French Committee in 1799. In 1873, metric weights were extended to silver coins. The weight of the half dollar is 12.5 grams; the quarter 6.25 grams; the nickel is 5 grams and the dime is 2.5 grams. In 1875 the United States entered into a treaty with 17 other countries establishing the International Bureau of Weights and Measures. In 1890, the United States received two of the International prototype metres and two of the kilogram artifacts. One of each of these standards was adopted as the National Prototype Metre and Kilogram and as the primary standards for the United States. As such they became the fundamental standards for determining the yard and the pound. The prototype metres and kilograms are preserved at the National Bureau of Standards. In 1896, and again in 1901, bills were introduced recommending the adoption of the metric system for all weights and measures in the United States, but for one reason or another the bills failed to pass. In the years following, many bills have been introduced which recommended establishing the metric system as the legal standard of the United States, however, very little action has been taken.

In 1968, Congress asked for a three-year, sweeping investigation of the metric question because it determined that the world trend toward metric called for a new assessment. The investigation involved public hearings, supplemented by surveys on international trade, business, and industry, education, national security -- almost every activity in our society -- and in 1971, the final report titled A Metric America -- A Decision Whose Time Has Come was released. It consisted of the comprehensive report plus twelve sub-study reports covering all aspects of the study.

Finally, in 1975 Congress passed the Metric Conversion Act. The major provisions of the bill provide for:

Adaptation of SI as predominant system of measurement units

No specific timetable

Voluntary participation

A Metric Board

Costs of Conversion

treat as other costs of doing business

no tax credits or subsidies

hardship cases to be reviewed by Board

Significant Dates In U.S. Metric History

1791 - "Jefferson Report." Thomas Jefferson described England's weight and measures standards to Congress "on the supposition that the present measures are to be retained," and also outlined a decimal system of weights and measures of Jefferson's conception.

1821 - "Adams Report." John Quincy Adams recommended to Congress that they act to bring about uniformity in weights and measures, and described France's young Metric System as a praiseworthy attempt at uniformity.

1866 - "Law of 1866." Congress made use of the Metric System legally permissible throughout the United States.

1875 - "Treaty of the Meter." On May 20, the United States entered into a treaty with 17 powers establishing the International Bureau of Weights and Measures, and providing for its administration.

1890 - The United States officially received Metre No. 27 and Kilogram No. 20.

1893 - "The Mendenhall Order." The Secretary of the Treasury announced that the International metre and kilogram would be regarded as fundamental standards by the Office of Standard Weights and Measures (which became the National Bureau of Standards in 1901).

1902 - A bill brought before the Congress to make the Metric System mandatory within the Federal Government was defeated.

1957 - In September, a committee of the Organization of American States proposed that the Metric System be adopted throughout the Western Hemisphere.

1959 - Australia, Canada, New Zealand, South Africa, the United Kingdom, and the United States adopted common standards for the inch-pound system in metric terms. One inch was made equivalent to 2.54 centimetres and 1 pound was made equivalent to 0.453 592 37 kilograms. (The Coast and Geodetic Survey, which had used a slightly different conversion factor previously, retained their established relationship of 1 inch equaling 2.540.005 centimetres because of the extensive revisions which would be necessary to their charts and measurement records. The resulting foot based on this retained conversion is known as the U.S. Survey foot).

1965 - On May 24, the British Board of Trade announced that the government consider it desirable to adopt metric units in the United Kingdom, with a target date for conversion of 10 years.

1968 - An Act providing for a 3-year program to determine the impact of increasing use of the metric system on the United States was passed by Congress and signed into law by the President.

1969 - New Zealand began an eight-year conversion to metric units.

1970 - Australia announced plans for a 10-year change over to SI metric measurement.

1970 - Canada announced its commitment to metric conversion.

1971 - The comprehensive report on the U.S. Metric study titled A Metric America: A Decision Whose Time Has Come is released.

1973 - The American National Standards Institute established the American National Metric Council with offices in Washington, D.C.

1974 - Congress passed the first official legislation concerning conversion to the metric system as part of Public Law 93-380, to extend and amend the Elementary and Secondary Education Act of 1965. Under section 403 of this Act entitled, "Education for the Use of the Metric System of Measurement", it states "the metric system of measurement will have increased use in the United States, and as such, the metric system will become the dominant system of weights and measures in the United States."

1975 - Congress passed the Metric Conversion Act.

1976 - The U.S. Metric Board is appointed.