Another factor in transportation bearing upon the problem of marketing is the control by food manufacturing and marketing concerns of refrigeration and other special types of cars. This special control has grown up largely because, owing to seasonal changes in regional occupation for these cars over different parts of the country, no one railway wished to provide sufficient special cars and service for use that may come its way only part of the year. The result has been to force the building up of a domination by certain concerns who control many of the cars and stifle free competition. Much the same results have been attained by special groups in control of stock yards and, in some cases, of elevators. Where such formal or informal monopolies grow up, they are public utilities, and if the farmer is to have a free market they must be replaced by constructive public service. A FREE MARKET Every impediment to free marketing in produce either gives special privileges or increases the risks which the farmer must pay for in diminished returns. We have some commodities where manufacture has grown into such units that these units exert such an influence that they consciously or unconsciously affect the price levels of the farmer's produce. When a few concerns have the duty of manufacturing and storing the seasonal reserves in a single commodity they naturally reduce prices during the heavy production season and increase them in the short season as a method of diminishing their risk and increasing profits. Moreover, their tendency is often to sell the minor portion of their product that goes for export at lower than the domestic price in order to dispose of it without depressing local prices. They do not need to conspire, for there can be perfectly coincident action to meet the same economic currents. Such coincidence has much greater possibilities of general influence with a few concerns in the field than if there were many.