Frank Pula, age 13, of St. Catharines, Ontario, Canada, for his question:

What exactly is the metric system?

This number system is as simple as counting on your ten fingers. Napoleon Bonaparte, Emperor of France, directed his scientists to devise something simple to replace the bewildering systems of measurements used throughout his empire. Perhaps, like other military conquerors, he wanted to donate at least one useful gift to the world. In any case, the world certainly needed the metric system.

There are, as you know, 12 inches in a foot and 16 ounces in a pound, two pints in a quart and three feet in a yard, 2,000 pounds in a ton and 5,280 feet in a mile. What a mess. It's too bad that all the time spent learning this bewildering configuration, and coping with it, is quite unnecessary. In the 1790s, French scientists devised a simple system to do the whole .job with ten fingers. They worked out the metric system in which all those units are based on ten. They also gave the units names that tell whether they are ten times smaller or larger    100 or 1,000 times larger or smaller.

In the long measure department, the basic unit is the meter. Using ten to multiply or divide, we can parcel out the meter in larger or smaller units. One meter equals ten decimeters or 100 centimeters. One centimeter equals 10 millimeters  and it's no problem to figure that 1,000 millimeters equal one meter. For longer distances, multiply the meter by 1,000 and stride off a kilometer. This simplified scale of long measure also includes other larger and smaller units    all based on multiples of ten and related to the basic meter.

The meter also is the basic unit for the decimal scales of weight and capacity. One liter equals the liquid water required to fill one cubic decimeter, precisely measured at its greatest density. It is used to measure milk. The decaliter equals ten liters, the hectoliter equals 100 liters. These larger units are used to measure grain and barrels of liquid.

The metric scale of weights is based on the gram'   and the gram also is related to the meter. It is the weight of one cubic centimeter of water, precisely measured at its greatest density. The decogram is ten grams, the hectogram is 100 grams. The kilogram is 1,000 grams and the metric ton equals 1,000 kilograms. All this is very neat. But when it comes to translating the different scales, the system is even neater. One cubic decimeter of distilled water, chilled to its greatest density, weighs one kilogram. There are 1,000 cubic centimeters in the cubic decimeter and 1,000 grams in the kilogram. Translating the marvelous metric system into our disjointed units is more cumbersome. The meter itself equals 1.093 of our yards, or 39.37 inches    and the kilometer equals 0.621 of one mile. The liter equals 1.056 U.S. quarts or 0.880 English quarts, and the kilogram equals 2.2046 pounds.

France adopted the metric system in 1799 and many other countries adopted it later. The British Commonwealth of Nations is rather slow to remodel old customs, but even they are preparing to change to the metric system. Someday, it is hoped that the United States will also bring its everyday measuring units up to date. However, in the meantime, the time saving, brain saving metric system has been adopted by scientists of every country.