The average price charged for the transportation of merchandise by the old method is eighteen centimes per ton and kilometer, the merchandise taken and delivered at the warehouses. It has been calculated that, at this price, an ordinary railroad corporation would net a profit of not quite ten per cent., nearly the same as the profit made by the old method. But let us admit that the rapidity of transportation by rail is to that by wheels, all allowances made, as four to one: in society time itself being value, at the same price the railroad would have an advantage over the stage-wagon of four hundred per cent. `Nevertheless, this enormous advantage, a very real one so far as society is concerned, is by no means realized in a like proportion by the carrier, who, while he adds four hundred per cent. to the social value, makes personally less than ten per cent. Suppose, in fact, to make the thing still clearer, that the railroad should raise its price to twenty- five centimes, the rate by the old method remaining at eighteen; it would lose immediately all its consignments; shippers, consignees, everybody would return to the stage-wagon, if necessary. The locomotive would be abandoned; a social advantage of four hundred per cent. would be sacrificed to a private loss of thirty-three per cent. The reason of this is easily seen. The advantage which results from the rapidity of the railroad is wholly social, and each individual participates in it only in a very slight degree (do not forget that we are speaking now only of the transportation of merchandise); while the loss falls directly and personally on the consumer. A special profit of four hundred per cent. in a society composed of say a million of men represents four ten-thousandths for each individual; while a loss to the consumer of thirty-three per cent. means a social deficit of thirty- three millions. Private interest and collective interest, seemingly so divergent at first blush, are therefore perfectly identical and equal: and this example may serve to show already how economic science reconciles all interests. Consequently, in order that society may realize the profit above supposed, it is absolutely necessary that the railroad's prices shall not exceed, or shall exceed but very little, those of the stage-wagon. But, that this condition may be fulfilled,--in other words, that the railroad may be commercially possible,--the amount of matter transported must be sufficiently great to cover at least the interest on the capital invested and the running expenses of the road. Then a railroad's first condition of existence is a large circulation, which implies a still larger production and a vast amount of exchanges.