Similar conditions, affecting every market for any commodity, may easily be discovered. Yet in spite of all these extreme fluctuations, no better test of value has been suggested than the market price in open, unrestrained competition of buyers and sellers.
_The market price._--In the discussion of value so far, the term market price has been used because perfectly familiar to everyone. It is necessary, however, to call attention to the fact that price always indicates an estimate of value in units of current money. If that money itself has a fluctuating value, the same article may have at different times different prices with the same value, or the same price with different values. Thus market prices in our country during and after the civil war, in which a paper currency gave the unit of prices, cannot safely be compared with each other, and can far less be compared with prices upon a specie basis.
Even the reduction to a so-called gold basis may give misleading ideas in regard to the market, since a new element of speculation in gold enters into the calculation. In all the accompanying illustrations of fluctuating prices, this particular abnormal condition has been carefully excluded. Any fluctuations in the value of money metals, necessarily affecting the relation of market price to market value, will be treated under standards of price in Chapter X.
_Prices of farm products; the crop year._--The actual fluctuations of market prices under the law of supply and demand can be most clearly seen by a careful study in the same definite market during a period of years. For illustration here the staple products of the farm have been chosen, and the markets of Chicago and New York, as most truly representative, have furnished the facts for study. These facts are presented to the eye directly by a series of charts, each of which has been most carefully prepared from official records, and gives within narrow limits a large range of investigation. In every case involving annual crops, it seemed necessary to rearrange statistics so as to cover the actual year affected by the crop in question. September 1 was chosen as the beginning of each year, because that date is nearest the time when the new crop of the season appears in market and directly affects the price of such products in store. All calculations upon live stock have been brought to the same basis, for the reason that the supply of marketable stock is largely dependent upon the supply of feed for stock. It seems very desirable that all statistics in regard to markets and productive industry should be brought to a uniform year. The year given in these charts seemed best to suit the subjects treated. It is possible, however, that for all data convenience would settle upon July 1, the beginning of the fiscal year in the United States, as the best for beginning the universal statistical year. Each chart in the series, of course, requires its particular explanation.