The freight service of the railroads of the United States, measured by weight, in 1910, amounted to 1,026,000,000 tons. Only since 1899 when the corresponding figure given by the Interstate Commerce Commission was 501,000,000 tons, have accurate data been obtainable. This would indicate a growth in ten years of about one hundred per cent. But this figure takes no account of the distance each ton of freight travels. This factor is included in what is known as ton mileage--that is to say, the equivalent of the number of tons of freight carried one mile. Obviously, so far as the amount of service rendered is concerned, one ton carried a hundred miles is the equivalent of one hundred tons transported one mile. Every carrier totalizes in this way each ton of freight movement by multiplying it into the distance transported. For the United States as a whole, this ton mileage in 1910 was 255,016,000,000--that is to say, the service rendered would be represented by the carriage of that number of tons one mile. The appended diagram shows the phenomenal rapidity with which this transportation service has grown since 1899. The scale on the left hand side of the chart serves this purpose. The right hand scale indicates the miles of line in operation. [Illustration: Relative Growth of Mileage and Traffic] The rapid growth up to 1893 was suddenly interrupted by panic and subsequent industrial depression lasting for about four years. Recovery began in 1897, since which time the freight movement has increased by leaps and bounds from about 95,000,000,000 ton miles to 255,016,000,000 ton miles in 1910. It is obvious that the growth of transportation in any country is bound to be more rapid than the increase either in population or in wealth. It appears, indeed, almost as if the volume of transportation in the United States increased more nearly as the square of population than in direct proportion. It has been estimated that we forward two and a half times as much freight _per capita_ as some of the leading European countries like France. Our domestic population from 1890 to 1910 increased about fifty per cent. The railroad mileage grew at about the same rate. Yet the freight service surpassed this rate of growth more than six times over; and the passenger service augmented nearly as much. Both alike in 1910 were practically three times as great in volume as twenty years before. The diagram on page 78 is intended to illustrate the relative rapidity of this development. While population and mileage increased about one half, the railroads in 1910 hauled the equivalent of three times the volume of freight traffic handled in 1890. At the beginning of this period, the railroads had to seek the freight. Now it appears that traffic normally will seek the railroads. At times, even, as in 1906-1907, the railroads have actually sought to escape the flood of business presented.