A century or more ago, each centre of population in the United States was practically self-sustaining. Each grew its own food-stuffs, and manufactured the articles used in the household. But very little was required in the way of transportation. The means of carriage were mainly ox-carts, pack-horses, and rafts. There was a mutual independence among the various centres, it is true, but the independence was at the expense of civilization and the comforts of life. [Illustration: OCEAN TRANSPORTATION--ROYAL MAIL STEAMSHIP OCEANIC, WHITE STAR LINE] Beyond an independence that is more apparent than real, such a plan of social and industrial organization has but little in it to commend. Intercommunication increases knowledge, and under the conditions that formerly prevailed, there was a lack of the breadth of knowledge that comes with the mutual contact of peoples. The utilization of national resources, such as the productiveness of the land, the existence of iron ore, coal, copper, and other economic minerals, finally brought about the policy of a territorial division of industries. This, in turn, made the prompt transportation and exchange of commodities essential; indeed, without such a plan, industrial centres could not long exist. The man whose sole business is manufacture must look to others for his supply of food-stuffs and raw materials, and these are produced more economically at a distance from the centre of manufacture. Thus England must look to the United States for wheat and cotton, to the Australian Commonwealth for wool, and to New Zealand and the United States for meat. Her chief wealth is in her coal and iron, and these make the nation a great manufacturing centre. So, also, the manufacturer of New York must go to Pittsburg for steel, to Minneapolis for flour, and to Chicago for beef. The application of this principle is very broad; it is the foundation of all commerce, and it underlies modern civilization. For this reason the question of transportation is just as important to a community as the industries of agriculture, mining, and manufacture. Food-stuffs are of no use unless they can be transported to the people who want them; nor can peoples remain in unproductive regions unless the food-stuffs are brought to them. The gross tonnage of goods is transported mainly in one or another or all of three ways--namely, by animal power, by railway, or by water. Thus, the cotton-crop of the United States is usually transported by wagon from the plantation to the nearest station or boat-landing; by rail or by barge to the nearest seaport; and by ocean steamship to the foreign seaport.