Every now and then some one who has not given much thought to the matter asks the questions, “Of what real use is the Stock Exchange?” “What does it accomplish?” “Is it a necessary and useful part of our economic life, or is it merely a means of promoting speculation and gambling?” These are fair questions, and they are asked in good faith. To be sure they have been answered many times by writers on economic subjects, but the trouble is that in our hurried American life we do not read the economists, preferring to get our impressions from the hasty utterances of some one who knows no more about it than we do. The study of any form of economic development, like the study of sciences and philosophies, requires infinite patience. But the “man in the street” is bored to death by such methods; he wants to take a short cut to his conclusions; merely tasting the Pierian spring he hurries on to judgments that are superficial, haphazard, and often crude and blundering. And yet at bottom this man, a good citizen with an open mind, invariably wants the truth. He may be too busy to dig it up himself, but he knows it when he sees it, and once he has grasped it he has no patience with those who seek to turn him from it. To this average man, who holds in his hands the balance of power in America, I venture to say something about markets. The first thing a man asks when he wishes to buy is “the price.” Every minute of the day, all over the world, that question is on men’s lips. As it is a necessary prelude to all forms of trade, it follows that everything that enters into the making of prices becomes at once of primary importance. The more scientific the price, and the nicer and more accurate the making of it, the better the bargain for both buyer and seller and for trade generally, bearing in mind the distinction between prices, which are temporary and move rapidly--and values, which are intrinsic and move slowly. The price of a thing is what you can get for it; the value is its real worth to you, and hence it cannot be defined or measured, since a thousand considerations may enter into it, such as caprice, sentiment or association. If _real_ values could be determined, they would necessarily be identical with prices, but as they cannot be ascertained in ordinary commodities of trade, prices become the really essential considerations and values the subordinate ones. Let us see, then, how prices are made, for this is one of the reasons why exchanges exist.