Sixty great dredges were employed on the work, and the dredged material was discharged in chutes on to the bank. The canal was the work of M. De Lesseps, the eminent French engineer, and has proved a great success from both an engineering and financial standpoint. The stock is mainly held in England, having been bought from the Khedive of Egypt. In 1898 the ships passing through the canal during the year reached the remarkable number of 3,503. The rate of tolls is 10 francs (about $2) per net ton. The gross tonnage of ships passing through in 1898 was 12,962,632, the net tonnage 9,238,603. The total receipts for the year were 87,906,255 francs (about $17,500,000), and the net profit 63,441,987 francs (about $12,500,000). An average size ocean liner pays about $5,000 for the privilege of sailing through this great ditch. Admiral Dewey’s ship, the “Olympia,” returning from the Philippines, paid for her toll $3,516.04, and the “Chicago,” $3,165.95. Going the other way, our supply ship “Alexander” paid $4,107.99, while the “Glacier” paid $5,052.38. Ships making the passage through the canal move slowly on account of the washing of the banks, about 22 hours being required, but the shortening of the travel of ships going east and west, and the saving of life, property, and time, involved in avoiding the circuitous and stormy passage around the Cape of Good Hope, has been of incalculable benefit to the world. [Illustration: FIG. 232.--HERCULES DREDGER.] With the construction of canals and harbors, great improvements have been made in dredges. Some of these are of the clam-shell type, some employ the scoop and lever, others an endless series of buckets. An example of the latter, used on the Panama Canal, is seen in Fig. 232. Still another form, and the most recent if not the most important is the hydraulic dredger, which, by rotating cutters, stirs and cuts the mud and silt, and by powerful suction pumps and immense tubes draws up the semi-fluid mass and sends it to suitable points of discharge. The best known of the latter type is the Bowers hydraulic dredge, covered by many patents, of which Nos. 318,859 and 318,860, May 26, 1885; 388,253, August 21, 1888; and 484,763, October 18, 1892, are the most important.