The original English definition of an inch was "three barley corns" with rounded ends. The meter is 1/10,000,000 (one ten-millionth) of a quadrant of the earth's circumference, i. e., the distance from the pole to the equator measured along one of the meridians of longitude. The length of three barley corns might be different from the next three, so here was the original difficulty again. The designers of the metric system went back to the earth itself as the only unchangeable thing—and—are we sure there is no change in the earth's circumference? The great advantage of the metric is that it is a decimal system and includes weights as well as surfaces and solids. Our weights are even more distracting than our long measure. We have in fact two kinds of weight measure—troy and avoirdupois.
| TROY | | | | 24 gr. | = 1 pwt. | | 20 pwt. | = 1 oz. | | 12 oz. | = 1 lb. | | 5760 gr. | = 1 lb. |
| | AVOIRDUPOIS | | | | 16 oz. | = 1 lb. | | 112 lb. | = 1 cwt. | | 20 cwt. | = 1 ton | | 2240 lb. | = 1 long ton | | 2000 lb. | = 1 short ton | | 100 lb. | = 1 short cwt. | | 7000 gr. | = 1 lb. |
| | METRIC | | | | | . | 001 | milligram | | | . | 01 | centigram | | | . | 1 | decigram | | 1 | . | | gram | | 10 | . | | dekigram | | 100 | . | | hectogram | | 1000 | . | | kilogram |
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In surface measurements, the same differences are seen:
| AMERICAN OR ENGLISH | | | | 9 | | sq. ft. | = 1 sq. yd. | | 30 | 1⁄4 | sq. yds. | = 1 sq. rod | | 160 | | sq. rods | }
} | = 1 acre | | 4840 | | sq. yds. | | 640 | | acres | = 1 sq. mile |
| | METRIC | | | | | . | 0001 | sq. centimetre | | | . | 01 | sq. decimetre | | 1 | . | | sq. metre | | 100 | . | | are | | 10,000 | . | | hectare | | 1,000,000 | . | | sq. kilometre |
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In measures of volumes we are as badly off:
| DRY | LIQUID | | | | 2 pints | = 1 quart | 2 pints | = 1 quart | | 8 quarts | = 1 peck | 4 qts. | = 1 gallon | | 4 pecks | = 1 bushel | 1 gal. | = 231 cu. ins. | | 4 quarts | = 268.8 cu. ins. | | | 1 heaped bushel | =11⁄4 struck bushels. | | The cone in a heaped bushel must be not less than 6 ins. high. |
| | METRIC | | | | | . | 001 | millilitre | | | . | 01 | centilitre | | | . | 1 | decilitre | | 1 | . | | litre or cu. decim. | | 100 | . | | dekalitre | | 1000 | . | | hectolitre |
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As if this were not enough, when we go to sea we use another system. The depth of water is measured in fathoms (6 feet = 1 fathom), the mile is 6086.07 feet long = 1.152664 land miles, and 3 sea miles = 1 league. In our cubic measure:
| 1728 cubic inches | = 1 cubic foot |
| 27 cubic feet | = 1 cubic yard |
| A cord of wood is 4 ft. × 4 ft. × 8 ft. | = 128 cubic feet. |
| A perch of masonry is 161⁄2 × 11⁄2 × 1 | = 24.75 cubic feet |
Isn't it about time we used the metric system? The reader will not mind one more standard unit. Lumber is measured by the board foot. Its dimensions are 12 × 12 × 1 inches; it contains 144 cubic inches and is 11⁄12 of a cubic foot. A board 10 feet long, 1 foot wide and 1 inch thick contains 10 board feet. One of the same length and width but only 1⁄2 inch thick contains 5 board feet.