The average ship costs about 10 cents per net registered ton per day for keeping it in operation. Thus a 10,000-ton ship will save about a thousand dollars for each day its voyage is shortened. If this voyage be shortened by 20 days, the shipowner makes a net saving of $8,000 when he selects the Panama route over some other route. In fact, he may save even more than this, for the other route might involve the giving of additional space for bunker coal, which otherwise would be used for cargo. Convenient coaling stations mean a minimum of space required for the operation of the ship and a maximum of cargo-carrying capacity. In this way a merchant ship might save several thousand dollars additional by choosing the Panama route over the Strait of Magellan. It is estimated that the tolls it will be necessary to collect to make the canal self-supporting will be $15,500,000 a year, since that amount will be required to meet the expense of operation and return 3 per cent interest on the investment. The $15,500,000 is made up of $3,500,000 for operations, $250,000 for sanitation and government and $11,250,000 for interest on the $375,000,000 the canal cost. This takes no account of approximately $10,000,000 which will be required for the support of the troops on the Isthmus. Should this be considered, the total annual charges to be made would approximate $25,000,000, but this, in the view of those who have considered the matter, is not a proper charge against the cost of operation. [Illustration: THE ANCON BASEBALL PARK] [Illustration: CALEB M. SAVILLE GATUN SPILLWAY FROM ABOVE AND BELOW] It has been stated that a proper system of finances would provide for the repayment of the cost of constructing the canal in a hundred years. This would mean an annual charge of $3,750,000, and would bring the total annual outlay, exclusive of the cost of protection, up to $19,250,000. From this viewpoint the canal will not be self-sustaining until the total traffic approximates 17,000,000 tons a year, which it will reach about 1925. It has been estimated by Prof. Emory R. Johnson, the Government expert on canal traffic, that the total tonnage which will pass through the canal during the first year of its operation will approximate 10,500,000 net registered tons. Since the shipping of the United States is permitted to pass through without paying tolls, the tonnage upon which toll will be collected will yield a gross revenue of approximately $10,000,000. This will afford the United States an income of a little less than 2 per cent on the money invested, after paying the actual cost of operation. On this basis it probably will be four or five years from the opening of the canal before the returns will yield 3 per cent on the investment.