Before proceeding to explain the proposed system, let me exhibit for one moment the necessity of change, as illustrated by weights and measures in the past.
Language is coeval with man as a social being. Weights and measures are hardly less early in origin. They are essential to the operations of society, and are naturally common to all who belong to the same social circle. At the beginning, each people had a system of its own; but as nations gradually intermingle and distant places are brought together by the attractions of commerce, the system of one nation becomes inadequate to the necessities of the composite body. A common system becomes important just in proportion to the community of interests. Next to diversity of languages, discordant weights and measures attest the insulation of nations.
The earliest measures were derived from the several parts of the human body. Such was the cubit, which was the distance between the elbow and the end of the middle finger, being about twenty-two inches. Such also were the foot, the hand, the span, the nail, and the thumb. These measures were derived from Nature, and they were to be found wherever a human being existed. But they partook of the uncertainty in the proportions of the human form. When Selden, in his “Table-Talk,” wittily likened Equity, so far as it depended on the Chancellor, to a measure determined by the length of the Chancellor’s foot, he exposed not only the uncertainty of Equity, but also the uncertainty of such a measure.
Even in Greece, where Art prevailed in the most beautiful forms, the famous _stadium_ was none the less uncertain. It was the distance that Hercules could run without taking breath, being six hundred times the length of his foot.
Our own standards, derived from England, are of an equally fanciful character. The unit of _length_ is the barley-corn, taken from the middle of the ear and well dried. Three of these in a straight line make an inch. The unit of _weight_ is a grain of wheat, taken, like the barley-corn, from the middle of the ear and well dried. Of these, twenty-four are equal to a pennyweight. Twenty pennyweights make an ounce, and twelve ounces make a pound. The unit of _capacity_ is derived from the weight of grains of wheat. Eight pounds of these make one gallon of wine measure.