WEIGHTS AND MEASURES There are four principal dasses of weights and measures, namely: Meas ures of Length, of Surface, of Vol ume, and of Weight. In addition to these are measures of value as ap plied to money and coinage--meas urement of time, temperature, and others. The principle underlying the use of weights and measures is that of reference to an agreed unit as standard. Some distinct means of de termirxing quantity is essential to the most primitive forms of human so ciety. Hence, the use of weights and measures is very ancient. As the ap plications of this principle have in creased in number and importance with advancing civilization, a great variety "of different units as standards of measurement, adapted to different purPoses, have been introduced. .The result is a great degree of confusion in the common mind on this subject which entails enormous loss and ex pense in all commercial business. An attempt has been made by scientific men to remedy this condition by the introduction of the metric system, but thus far this system has not come into general use in the English speaking world.
At present the units in general use in the United States are as follows: of measures of length, the unit for carpentry and mechanics is the foot. This is subdivided into inches and lines, or inches, halves, quarters, and so on. The unit for textile fabrics is the yard divided into quarters and nails. For field surveying, the chain divided into links and decimals. For road measure, the mile divided into furlongs and rods. The units of square or superficial measure are the squares of these with the addition as a unit for land measure of the acre. Of capacity measures, the units for liquids are the gallon, quart, pint, and gill. For cereals and other dry sub stances, the bushel and peck. For fire wood, the cord. The unit of weight for ordinary commerce is the avoir dupois pound, divided into halves, quarters, and so on; or, for large masses, into the quarter, hundred, and ton. The unit for bullion, plate, and coin, or jewelers' measure, is the pound troy which is irregularly di vided. The unit for drugs and medi cines, or apothecaries' measure, is a pound equal to the pound troy but differently subdivided. Jewelers also make use of a unit for the measure ment of gems called the carat.
Origin of Standards.—The deriva tion of the original units of linear measurement appears to have been from comparison with various parts of the human body. The use of the
foot seems to have originated in Greece, the standard, according to tra dition, having been taken from the foot of Hercules. The natural mode of measuring various distances by counting one's steps, which is still oc casionally made use of for rough measures, early gave rise to the pace as a unit or standard. Hence, the Roman mille passuum, 1,000 paces, from which has been derived the mile of the present day. The ancient cubit is taken from the length of the fore arm. This is still a standard of meas urement in many Eastern countries.2 The ell, a term used in Europe down to our own time for cloth measure, is also derived from the forearm. The English yard, from an old English term meaning to gird, signifies the girdle or circumference of the body. The fathom is from an old English word meaning to embrace and signi fies the length of two arms. The breadth of the hand or palm is still used as a standard in the measure ment of the height of horses. The nail and the thumb's breadth have also been frequently made use of.
Measurements of weight were a much later introduction. The wheat corn or grain of wheat, required by law to be taken from the middle of the ear, was used in England as a standard of weight until within mod ern times. With the introduction of modern science, the length of a pen dulum measuring seconds under cer tain prescribed conditions has been taken as a linear standard. And the weight of a prescribed quantity of water under certain conditions has been taken as a standard of weight. The standard of solid measure has also been similarly deterrained.
The unit of the metric system is the meter, intended to be one ten mil lionth of the distance from the equa tor to the pole. This unit has been agreed upon as a standard by the principal European nations and has been accepted by Great Britain and the United States, although its use is not compulsory in either of those countries. The standard units em ployed by the T.Jnited States Govern ment at Washington are themselves corrected by reference to the interna tional meter. Hence, the metric sys tem is actually the ultimate standard in the United States. It is to be very much regretted that the use of the metric system has not become univer sal. At present, it is employed by somewhat more than half the popula tion of the civilized world.