Due to the facts already mentioned, the number of mid-western farms increased nearly a million from 1870 to 1890, and the acreage in improved farm land grew by an amount equivalent to the combined areas of the British Isles, Belgium, the Netherlands, and Denmark, with a generous margin to spare. The production of corn, wheat, oats and other cereals became so great as to demand an outlet to the East and to the markets of the world. Elevators for the storage of grain were constructed with a capacity of 300,000 to 1,000,000 bushels, and improvements were made in the methods of loading and unloading the product. Despite the growth of the agricultural interests of the Middle West, however, the farmer did not reach prosperity. For twenty years after 1873 prices fell steadily both in the United States and in other countries of the world, and the agricultural classes found themselves receiving a smaller and smaller return for their products. Unrest grew to distress, and distress to acute depression, while the demands of the farmers for relief frequently determined the trend of mid-western politics.[3] [Illustration: Relative Prices--1865-1890] Less general than agriculture, but more characteristic of the period after the war, was the development of manufacturing. The census of 1870 was faulty and inadequate, but it was sufficiently accurate to indicate that the manufacturing region was preeminently that north of the Potomac-Ohio river line and east of the Mississippi. By 1890 it was apparent that the industrial interests were shifting slightly toward the West; nevertheless the leading states were those of southern New England, and New York, New Jersey and Pennsylvania. In these states no fewer than four hundred and forty-seven industries employed more than a million dollars of capital each. The manufacturing of cotton, woolen and silk for the rest of the country was done here; foundry products, iron and steel manufactures, silver and brass goods, refined petroleum, boots and shoes, paper and books, with a host of other articles, were sent from this section to every part of the world. All along the line, from Massachusetts to Pennsylvania, capital engaged in manufacturing doubled between 1880 and 1890, and the number of employees greatly increased. Although the industrial life of the South belongs, for the most part, to the years since 1890, the coal and iron deposits of Alabama were known and utilized before that year, the number of cotton mill spindles in North Carolina tripled between 1880 and 1890, and cotton expositions were held in Atlanta in 1881 and New Orleans in 1884. It was in the eighties, also, that the Chesapeake and Ohio Railroad and the Norfolk and Western led to the exploitation of the coal deposits of Virginia and West Virginia, especially the famous Pocahontas field.