VI. RAILROADS.

The achievements of engineering skill on the line of bridges, canals, tunnels, etc., have been great, but their effect is insignificant compared with the social revolution that was created by the invention and development of railroads. The railroads of this country represent a value of about $12,000,000,000—one sixth of the national wealth. Their pay-rolls include about 850,000 employees—1/28 of the working population. They support, directly or indirectly, about 5,000,000 people. They collect an annual revenue of about $1,200,000,000, which is greater than the value of the combined products of gold, silver, iron, coal, and other minerals, wheat, rye, oats, barley, potatoes, and tobacco, produced by the entire nation. Such a stupendous social institution requires special discussion, and it will be found treated separately under the heading of “Evolution of the Railway.”