Metric​—The Better Way

LEGEND has it that English King Edgar of the tenth century decreed the length of a yard to be the distance from the tip of his royal nose to the end of the middle finger on his outstretched hand. You can imagine how the yardstick must have varied from king to king!

The English also made other attempts to arrive at some sort of standard amid the jumble of weights and measures that prevailed for centuries. As late as the fourteenth century, King Edward II decreed that an inch was the combined length of three barleycorns, round and dry, taken from the center of the ear, and laid end to end.

Confusion reigned world wide for years when it came to doing business using such imprecise and changeable standards. Measures varied from country to country and town to town or even from merchant to merchant! And though the English system today is far more precise than it was then, it still leaves much to be desired.

A Complex System

The United States is the last major country still using the English system as its primary means of measuring. This system complicates the measuring process in several ways:

1. There are more than twenty-five different unit names for the various weights and measures​—miles, pounds, acres, gallons, bushels, and so on and on.

2. Many of the unit names have more than one meaning. For example, there are three kinds of pounds (Avoirdupois, Troy, Apothecary), four kinds of ounces (Avoirdupois, Troy, Apothecary, Fluid), and two kinds of tons (long, short). A quart by liquid measure has almost 15 percent less volume than a quart by dry measure.

3. There is no consistent relationship between the units of any measure: Yards are divided into thirds (feet), feet into twelfths (inches), pounds into sixteenths (ounces), ounces into eighths, sixteenths or twentieths (depending on the measure used), gallons into fourths (quarts), quarts into halves (pints), and so on.

4. There is little or no relationship between measures for length, weight or volume.

Learning such a complex system takes a lot of remembering for youngsters in school. Almost each unit of measure must be learned “from scratch.” Consequently, most people who use the U.S. customary measures learn to use less than half of the different unit names. But there is a better way.

The Metric Way

Back in 1790, shortly after their famous political revolution, the French National Assembly decided that France also needed to revolutionize its confusing system of weights and measures. A new basic unit of measure was chosen, based on something far more stable than the size of men or plants​—the earth itself. It was set at 1/10,000,000 of the distance between earth’s equator and the North Pole, and was called the meter (39.37 inches). Units of area, weight and volume were derived directly from the meter. Unit values were multiplied or divided merely by adding certain prefixes to the basic unit names.

In 1799, when the system finally became a fact for France, it was given the motto: “For all people, for all time.” But even though most of the world adopted the metric system during the ensuing two centuries, major English-speaking countries have been slow to make the change. Britain’s ten-year voluntary changeover plan fell far behind its scheduled 1975 completion, and Canada’s ten-year program has been moving slowly since 1970.

In the United States, the metric system has hardly gotten started. Finally, it was in December of 1975 that Public Law 94168 made the “coordination and planning of increasing use of the metric system” official government policy, and created a Metric Board to oversee an orderly voluntary transition.

What makes the metric system so superior? Why does even a commercial giant like the U.S., whose changeover costs will be huge, make such a change? If you do not already know the answers, you will find the chart at the right helpful. It shows how much simpler the metric system is.

Instead of over twenty-five different unit names, there are just three basic units, with prefixes, in the metric system! The same set of prefixes is used with all three units. The Greek prefixes deca-, hecto- and kilo- increase the units in multiples of ten, and the Latin prefixes deci-, centi- and milli- reduce them by submultiples of ten, as in the decimal system. Note how this is done, as shown in the chart below.

The prefixes hecto-, deca- and deci- are seldom used, so you can get along quite well by learning just the three basic units and three of the prefixes. For scientific and technical work, eight additional prefixes carry the base unit values up and down much further.

Instead of using inches, feet and miles to measure short, medium and long distances, all metric lengths are expressed in meters with the appropriate prefix: centimeters instead of inches, meters instead of feet or yards, and kilometers instead of miles.

Once the length of the meter and its decimal method of scaling up and down were set, the units of weight and volume were derived from it. A cube one centimeter on each edge became the milliliter 1/1,000 of the basic volume unit, the liter. The gram became the weight of this same milliliter filled with water!

Using the System

Not only is the metric system easier to learn, but it is also easier for most to use than the customary system. Fractions are almost eliminated in the metric system. Since every metric unit is a decimal value of those above and below it, most changes between units require only the moving of a decimal point. For example, to convert kilometers to meters just move the decimal point three places to the right, which automatically multiplies it by 1,000: 3.74 kilometers = 3,740 meters.

By contrast, to find the number of yards in 3.74 miles requires first knowing that there are 1,760 yards in a mile, and then multiplying that figure to arrive at 6,582.4 yards​—no small job if you don’t have a calculator handy. A U.S. Department of Commerce publication notes that “one authority is convinced that the U.S. aerospace industry alone would save about $65 million a year in engineers’ time by converting entirely to metric.”

At the supermarket, thrifty shoppers who compare prices will find that they need not convert pounds to ounces (16) or quarts to ounces (32) before dividing into the price to determine price per ounce. The metric weight or volume can be divided directly into the price in each case.

Often unawares, many Americans are already using the metric system. They use 35-millimeter film in their cameras, take 100-milligram doses of vitamins and use shortwave radios whose reception bands are expressed in meters. The events in the last Olympic games were all reported in metric terms. Some U.S. road signs already show both miles and kilometers, as do speedometers on newer cars.

How will people be affected as the metric system puts the other aside? Experience of others indicates that at first they will be prone to make conversions to the old system​—to see a meter as a long yard, a liter as an overgenerous quart, and a gram as the weight of a paper clip. However, as many travelers to Europe will testify, they soon begin to “think metric.” American products using metric specifications will begin to have more appeal on the world market.

Of course, a cup of coffee will still be a cup of coffee, and an inchworm an inchworm. Sayings such as “A miss is as good as a mile” will not be replaced with “A miss is as good as 1.6 kilometers.” But other things will change. A man’s 32-inch waist size will grow to 81 centimeters, while a 140-pound woman would weigh a petite 63.5 kilograms on the metric scale.

So, just as the ancient ephah, cubit and hin became measures that have meaning only to students of the past, eventually the inch, mile and ounce will probably follow those antiquated measures into the pages of history.

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Prefix Means Examples

Kilo 1,000 times kilometer = 1,000 meters

Hecto 100 times hectometer = 100 meters

Deca 10 times decameter = 10 meters

Deci 1/10 of decimeter = .1 meter

Centi 1/100 of centimeter = .01 meter

Milli 1/1,000 of millimeter = .001 meter

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U.S. Customary System Metric System

Length

League Prefix

Mile Plus:

Furlong

Chain

Rod

Fathom Meter

Yard

Foot

Inch

Mil

Weight

Ton

Hundredweight

Pound

Ounce Grama

Dram

Grain

Pennyweight

Scruple

Capacity

Bushel

Peck

Gallon

Quart

Pint Liter

Gill

Fluid Ounce

Fluidram

Minim

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POUND AVDP.

(16 OZ. AVDP.)

KILOGRAM

(35.27 OZ. AVDP.)

Basic metric units compared with U.S. customary measures

YARD (36 IN.)

METER (39.37 IN.)

QUART U.S., LIQ.

(32 OZ. U.S., FLUID)

LITER

(33.81 OZ. U.S., FLUID)

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METER

LITER

GRAM

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MILE

FOOT

POUND

PINT

GALLON

OUNCE

YARD

QUART

BUSHEL

INCH

PECK

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81

63.5