The catastrophe of 1873-'74 revealed the fact that the latter condition of railroad finances was vastly more common than had been suspected; and it is still doubtful whether the existing immense network of railroads which covers the United States can be made, as a whole, to pay even a moderate return on the money invested in their construction. At the period of maximum rate of extension of railroads in the United States--1873--the reported lengths of the railroads of Europe and America were as follows:[94] [94] _Railroad Gazette._ RAILROADS IN EUROPE AND AMERICA IN 1873. ----------------------------+------------+-------------+------------ COUNTRIES. | Railroads, | Population. | Area, | Miles. | | Sq. Miles. ----------------------------+------------+-------------+------------ United States | 71,565 | 40,232,000 | 2,492,316 Germany | 12,207 | 40,111,265 | 212,091 Austria | 5,865 | 35,943,592 | 227,234 France | 10,333 | 36,469,875 | 201,900 Russia in Europe | 7,044 | 71,207,794 | 1,992,574 Great Britain, 1872 | 15,814 | 31,817,108 | 120,769 Belgium | 1,301 | 4,839,094 | 11,412 Netherlands | 886 | 3,858,055 | 13,464 Switzerland | 820 | 2,669,095 | 15,233 Italy | 3,667 | 26,273,776 | 107,961 Denmark | 420 | 1,784,741 | 14,453 Spain | 3,401 | 16,301,850 | 182,758 Portugal | 453 | 3,987,867 | 36,510 Sweden and Norway | 1,049 | 5,860,122 | 188,771 Greece | 100 | 1,332,508 | 19,941 ----------------------------+------------+-------------+------------ The railroads in Great Britain comprise over 15,000 miles of track now being worked in the United Kingdom, on which have been expended $2,800,000,000. This sum is equal to five times the amount of the annual value of all the real property in Great Britain, and two-thirds of the national debt. After deducting all the working expenses, the gross net annual revenue of all the roads exceeds by $110,000,000 the total revenue from all sources of Belgium, Holland, Portugal, Denmark, Sweden and Norway. An army of 100,000 officers and servants is in the employ of the companies, and the value of the rolling-stock exceeds $150,000,000. SECTION III.--MARINE ENGINES.