Wise managers, if not misled by speculation in stocks, care more for enlarging traffic than for immediate returns upon a smaller bulk, because the bulk of profit is greater. A good illustration of development of a special traffic is found in the milk trains running two hundred or three hundred miles to supply the city of New York. The railroads are compelled by the needs of the traffic to carry the milk cheaply enough to prevent its being made into butter and cheese. Laws regulating this charge are effective, because such a necessity exists in the nature of the case.
_Weights and measures._--Another important growth in the machinery of trade is found in standards of quantity,--weights and measures of every kind. It is scarcely possible to realize the uncertainty of exchange without exact weights and measures. The story of the Indian trader who bought furs by weight, putting his hand upon the scales for one weight and his foot for its double, illustrates how uncertain such judgments of quantity may be without system. The present names of weights and measures indicate their origin in similar ways.
Measures have usually been connected with some part of the body: as "finger," used one way in measuring the load of a gun and another on a stocking; "hand," still used in measuring the height of horses; "span," once considered sufficiently definite for any measurement; "foot," now made to conform to an accurate system; and "pace," still used in many communities. Connected with the arm, are "cubit" and "yard." Many ladies still measure their dress goods by arm's lengths. For small measures, "grain" and "barley-corn," still used as names, indicate dependence upon average quantity in articles of general growth.
Today all civilized governments settle upon a definite system of measures and weights, all accurately connected with each other and with some precise dimension in nature supposed to be invariable. Our common yard is distinctly associated with a pendulum vibrating seconds; and in the great decimal system, adopted by most countries in Europe, and likely to be reached in all countries, the whole is connected with a measured meridian upon the earth's surface. Care is then taken to have standard measures and weights prepared in such a way as to be free from all effects of any change of temperature, and legal enactments distinctly define each measure and weight, actually punishing one for the crime of using false weights or measures. Units of quantity thus enter into all our calculations and form an essential basis of all exchange. Cheating in measure and weight grows less and less possible with this clear understanding of exact units. The New York Legislature has defined the size of fruit packages, and the Massachusetts poultry raisers ask a law requiring eggs to be sold by weight.
