So, in the general market, every seller gains what he desires more than what he possesses, and every buyer has exactly the same experience. Two friends may exchange books if either would be benefited by the exchange. In that case the one gaining the less valuable book gains the satisfaction of giving to his friend. Both are still profited, one by the larger value received, and the other by the pleasure of giving. In such an exchange no basis of value is reached, but in any ordinary bargain the final adjustment will be as nearly as possibly upon the test of value in the market. Between one buyer and one seller, the bargain is likely to turn to the advantage of the one who is quickest to discover the weakness of the other. If two persons are discussing the price of a house for which the seller wishes $1,000, but will sell for even $600, and for which the buyer hopes to give only $600, but will pay even $1,000, the seller will gradually lower his price, and the buyer gradually raise his offer until one or the other discovers the working of his neighbor’s mind. These are the natural conditions for sharp bargaining. In the larger market the interests of a multitude of buyers and a multitude of sellers have weight, and no shrewdness can prevent a settlement upon such a price as comes nearest to satisfying all parties. The so-called law of supply and demand is a brief statement of the fact that sales cannot be made in open market above the mark where buyers and sellers agree, and that mark is essentially the price at which all who are willing to buy at the price current are met by those who are willing to sell at the same current price. With reference, then, to all articles sold in open market, it is safe to say that the only test of value is the price which the public is willing to pay. So universal is the acceptance of this principle in practical affairs that everybody estimates the value of his property by the price at which it will sell. Any appraiser or assessor who should adopt a different principle would be considered wholly untrustworthy.