1. The Diminishing Importance of Agriculture in the Life of Man. Once agriculture was the all-embracing occupation. Practically all goods were produced upon the farm. Now, however, man's wants have so greatly increased that the primitive industries of the farm can no longer satisfy these wants, and in order to satisfy them men have developed large manufacturing industries. Moreover, fewer men are needed on the farms to produce the same amount of raw material as was produced formerly by the labor of many. This has come about mostly through labor-saving machines. The invention and application of labor-saving machines to the industries of the farm has made it possible to dispense with a great number of men. It is estimated that fifty men with modern farm machinery can do the work of five hundred European peasants without such machinery. Consequently, the four hundred and fifty who have been displaced by farm machinery must find other work, and they find it mainly in manufacturing industries. Again, the scientific and capitalistic agriculture of the present has much the same effect as labor-saving machines. They have greatly increased agricultural production and at the same time lessened the amount of labor. The opening up also of new and fertile regions which were very productive in the nineteenth century had a similar effect.
Every improvement in agricultural industry instead of keeping men on the farm has tended to drive them from it. Scientific agriculture carried on with modern machinery necessarily lessens the need of a great proportion of the population being employed to produce the foodstuff and other raw materials which the world needs. Hence it has tended to free men from the soil and to make it possible for a larger and larger number to go to the city. Therefore the relatively diminishing importance of agriculture has been one of the prime causes of the growth of the cities in the nineteenth century; and so far as we can see this cause will continue to operate for some time to come.
2. The Growth and Centralization of Manufacturing Industries. This is perhaps the most vital cause of the growth of cities. The great city, as we have already said, is very largely the product of modern industrialism. Improved machinery, improved transportation, and enlarged markets, together with the increased wants of men, not only have made possible a great growth of manufacturing industries, but also these same factors have tended to centralize manufacturing industries in the cities. Let us note briefly why it is that manufacturing industries are grouped together in great cities rather than scattered throughout the rural communities. In centralizing manufacturing plants in cities, certain industrial economies are secured, such as: (1) economy in motor power, whether it be water or coal; (2) economy in machinery—it is not necessary to duplicate machines; (3) economy in wages—one superintendent, for example, can oversee a large plant; (4) utilization of by-products—when many factories are grouped together by-products, which are sometimes more valuable than the main products, can be better utilized. (5) There is economy in buying raw material and in selling finished products when many factories are grouped together. For all these reasons, along with the further reason that those who labor in factories must live close to them, manufacturing has been a prime cause of the modern city, and, so far as we can see, will continue to further urbanize our population in the future.
3. The Increase of Trade and Commerce. Between different communities there developed during the nineteenth century, upon the growth of better transportation, a great increase of trade and commerce, for along with the better transportation went a specialization in industry, on the part of both communities and classes. The modern city is often largely a product of modern transportation. We find all the great cities located at natural breaks in transportation. The cities of the Middle Ages were largely centers of trade and commerce where goods were distributed to various minor centers. The modern city has not lost this characteristic through developing into an industrial center. On the contrary, the status of the city in trade and commerce makes it at the same time a valuable center for the development of manufacturing industries. The break between land and water transportation is particularly favorable to the development of large cities. Thus, we find New York located where goods shipped to Europe must be transferred from land to water transportation; Chicago, located at the head of the water transportation of the Great Lakes; St. Louis, at the head of the navigation of the Mississippi River. Only Denver and Indianapolis among the great cities of the United States in 1910 are not located on a river or some other navigable water.
Minor Causes. These are the chief social causes of the growth of cities, and, as we have seen, they are wholly industrial in their nature. Undoubtedly the modern city is a product of modern industry. Certain non-economic factors may also enter into the growth of cities, but these are of but slight importance; such are the greater intellectual and educational advantages which the city offers, the great opportunities for pleasure and amusement in the city and the like. Such minor and individual causes have had but little part in the growth of the great cities of the present.
Social And Moral Conditions Of City Life.—Certain social conditions in our cities are worthy of attention in order that we may understand the effect of the city upon social and racial evolution.
1. City Populations have a Larger per Cent of Females than Rural Populations. All of our fifteen largest cities, except three, contain a larger per cent of females than the states in which they are located. Thus New York state has 50.37 per cent of its population female; New York city, 50.56 per cent; Pennsylvania, 49.29 per cent of its population female; Philadelphia, 51.18 per cent; Missouri, 48.38 per cent of its population female; St. Louis, 49.51 per cent. In towns of the United States of more than 2500 population the per cent of females is 50.03, while the rural districts of the United States have only 48.08 per cent of their population female. The cause of this is perhaps to be found in the fact that in cities there is always a larger infantile mortality among males than among females, and that in towns there is a larger proportion of female children born than in the rural districts.
2. People in the Active Period of Life, from Fifteen to Sixty-five Years of Age, predominate in the City. According to Dr. Weber, out of every 1000 individuals in the United States as a whole there are 355 under fifteen years of age, 603 between fifteen and sixty-five, and 29 above sixty-five years of age. But in the great cities there are only 299 under fifteen years of age, and only 29 above sixty-five years of age, while 668 are of the age between fifteen and sixty-five years. (In both cases the age of three in a thousand was unknown.) The cause of the predominance of those in the active period of life is undoubtedly due to the immigration into the cities from the country districts. This makes the life of cities more energetic and active, more strenuous than it would otherwise be.
3. The Great Cities in the United States have over twice as many Foreign-born in their Population as the United States as a whole. This has been sufficiently discussed under the head of immigration.
4. The Birth Rate is higher in the Cities than in the Rural Districts. This is primarily due to there being more women of child-bearing age in the cities. In the United States it is also due to the presence of so many foreign-born in the cities. The marriage rate is also higher in the cities than in the rural districts. The following statistics based on a thousand population show the relative difference between the cities and the rural districts of the New England States in marriage rate, birth rate, and death rate for 1894-95: