478 AMERICAN ANTHROPOLOGIST [n. s., i, 1899
not give units in terms of motion, but units in terms of one mode of motion, which is gravity ; therefore the units are in terms of force. There are other units of measurements devised in the arts, as for example those for light, heat, steam, electricity, etc., but we will not consider them here.
The common units of measure are units of space or of gravity. Governments prescribe the units of measurement in the interest of justice, and the instruments of measurement are regulated by law and kept under government surveillance.
The unit for the measurement of values is of gold or silver, one or both ; in the case of both, the ratio is established. These units of value are coined in pieces as forms, and the government stamp gives warrant to the correctness of the amount of metal which they contain. If the government guarantee also their relative value, questions of great importance arise and these create political policies. If the government coins only for itself, and purchases the metal which it coins, it matters not what the ratio may be. If it coins at a ratio which is not the market value of the metals, the more valuable metal at the ratio adopted will give value to the coins of the less valuable metal, and both classes of coins will circulate at the value established by law. If the mints of the government are free to coin both metals for the public, and the legal ratio differs from the market ratio, the metal of lesser ratio value only will be offered for coinage, and the coins of the metal of greater ratio value will be driven out of circulation. Thus, in considering measurement of values many questions arise which are supposed to bear on the prosperity of mankind and especially on the people of a nation.
But why are statistics collected? The statistics of population in the United States are collected as a government function either by the nation or by the state for the purpose of fixing the basis of representation. Membership in the national and state councils is apportioned on the basis of population. The statistics of population, therefore, under our form of government, are
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