Dr. Weber in his _Growth of Cities in the Nineteenth Century_ illustrates the striking difference between the urban development of the nineteenth century and that of the eighteenth century by comparing the population of Australia in 1890 with the population of the United States in 1790. Australia in 1890, out of a population of 3,809,000 had 1,264,000, or 33.2 per cent, living in cities of 10,000 or over; while the United States in 1790, out of a population of 3,929,000 had only 123,000, or 3.14 per cent living in cities. Both countries, it will be noticed, had about the same total population at the two periods and the same area, but Australia in 1890 represented in its population the industrial development of the nineteenth century with its tendency toward urbanization, while the United States in 1790 represented the civilization of the eighteenth century with its predominating rural life. The Growth of Cities in the United States.--A word about census terminology will be helpful before discussing the growth of cities in the United States. According to the United States census, a city is a place with a population of 8000 or over; a _small_ city is a place with a population of 8000 to 25,000; a _large_ city is a place with a population of from 25,000 to 100,000, and a _great_ city is a place with a population above 100,000. These distinctions are necessary in discussing the problems of the city, because the problems of cities change rapidly when the population goes above 100,000. It is mainly the problem of the great city which we shall discuss in this chapter. In 1800 there were only six cities in the United States with over 8000 population. Philadelphia was the largest of these, with 69,000, and New York second with 60,000. These cities contained a fraction less than four per cent of the population of the United States. In 1900, on the other hand, there were 546 cities in the United States with a population of over 8000. Moreover, over thirty-three per cent of the total population of the United States lived in cities of 8000 and over, while nearly one fifth of the total population lived in the thirty-eight great cities. Between 1890 and 1900 the gain in the urban population of the country was sixty per cent, while the gain in the rural population was only fifteen per cent. During that decade, in other words, the cities grew four times as fast as the country districts in population. Moreover, for that particular decade, the great cities grew faster than the smaller ones, but since 1900 certain state census statistics seem to show that the cities from 25,000 to 100,000 population are growing faster than those above 100,000.