If we compare the year 1869—probably the last in which the Pacific Mail and the Huntington interests were in active competition—with the year 1884, it appears that the value of commodities shipped in and out of San Francisco via Panama during these years declined from about seventy to about two million dollars. Doubtless this falling off was not all due to agreements between rail and water carriers. For instance the sudden decline between 1869 and 1870 was occasioned in large part by the sudden diversion of bullion shipments from the water routes when the rail lines were opened, while passengers also rapidly deserted the water for the more speedy and comfortable rail service. Moreover, at a slightly later date the special contract system played its part in limiting shipments by sea. Yet it is not unfair to credit the arrangements between the Huntington group and the Pacific Mail with a considerable share of the reduction in water tonnage so desirable from the point of view of the land carriers. Pacific Mail and Panama Railroad The difficulty in bringing about a substantial lessening of competition by agreement with a water carrier is found in the fact that the sea is free, so that new ships and new shipping companies can readily take the place of those that are withdrawn. The peculiar strength of the Pacific Mail in negotiating with the railroad company lay in the fact that it enjoyed for many years the exclusive privilege of through-billing freight between San Francisco and New York, including the privilege of quoting a through rate. From all other steamship companies the Panama Railroad exacted a local rate for hauling freight across the Isthmus.[357] Inasmuch as this local rate was very high, it was impossible for a competing steamship company to handle through business at a profit. It was thus the railroad which determined whether competition by way of the Isthmus of Panama should succeed or fail. It may be added that after the year 1893 the Panama Railroad assumed the responsibility not only of the rail haul across the Isthmus, but of the water connection between Colon and New York as well, thus becoming the preponderant partner in respect to length of route, as well as in respect to strategic position. In return for the exclusive right of through-billing, and of quoting through rates, as well as for its agreements not to operate vessels in the Pacific, the Panama Railroad was promised a certain division of the through rate, which was not to be less monthly than a stipulated minimum. The minimum varied, but always was a substantial part of the payment which the transcontinental railroads were making to the Pacific Mail. In 1878 the railroads guaranteed the Pacific Mail $90,000 a month, out of which the Panama Railroad received $75,000. When the Pacific Mail subsidy was lowered from $90,000 to $75,000, the amount guaranteed to the Panama Railroad fell off from $75,000 to $55,000.