=The Three Fields of Commerce.=—In order to clarify the relations of government to commerce it is necessary, at the outset, to distinguish between three fields or types of commerce. The first is _local or intra-state_ commerce, which comprises all the trading operations carried on within the boundaries of a single state. Goods produced in Pittsburgh and marketed in Philadelphia are said to be within the sphere of local or intra-state commerce. As such they are wholly within the jurisdiction of the state of Pennsylvania. In the second place there is a large amount of commerce which, originating in one state, crosses into another. Shoes made in Massachusetts are shipped to Indiana; cotton grown in Georgia is sent to New York to be manufactured. This is called _national or inter-state_ commerce and it is under the jurisdiction of the federal government. Finally, trade is carried on between the United States and foreign countries and this is known as _international_ commerce. It also is subject to regulation by the federal government. [Sidenote: The state governments control local commerce.] =Local Commerce.=—Each state makes provision for the encouragement and regulation of commerce within its own territory. The communities and the state provide the improved roads which are essential for trade between country and town. The development of motor cars, motor trucks, and suburban trolley lines has greatly increased the facility with which this trade can be carried on. Each state, again, has control over the street railways, short-line railroads, and other channels of commerce within its own borders. This control is exercised through provisions of laws made by the state legislatures, but the enforcement of these regulations is usually placed in the hands of one or more boards, commonly known as public service commissions (see pp. 480-481). It is the duty of these commissions to see that the rates charged are reasonable and that adequate service is rendered. The jurisdiction of the state authorities, it should be repeated, does not extend over any commercial operations which are not strictly local; if the commerce concerns more than a single state it can be regulated only by the national government. INTERSTATE COMMERCE AND THE RAILROADS [Sidenote: Interstate commerce in early days.]