The third group of natural resources which we will notice in this connection comprises water power and the fisheries. For many years after steam began to be successfully applied to drive machinery, the waterfalls of our country remained unimportant sources of natural power. The discovery of electrical energy and of methods to apply it to machinery and to transmit it great distances, once more called attention to the desirability of utilizing waterfalls as a source of mechanical power. The successful attempt to harness Niagara Falls has been followed with similar successes in other sections, until it now appears that it is only a question of time until every waterfall in the country will be the seat of electrical generating plants.

In recounting the wealth of our natural resources we are likely to overlook the fisheries, which are the basis of the

Elementary Economics prosperity of many localities. The sea fishing of all three coasts is a profitable industry, giving employment to thousands of men and boys and furnishing one of our most important supplies of food. On the Great Lakes, and along the rivers also, fishing is important. Fortunately for the fishing industry, the national government and many of the states have enacted laws designed to prevent waste and depletion. To that end, restrictions are placed as to the time and methods of catching fish; and the stocks of fish are replenished periodically from public hatcheries.