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18

wide. The current having proved rather slower in scouring out the channel than was anticipated, and it being necessary to attain a proper depth before the transcontinental traffic could be successfully inaugurated, the work of the current has lately been supplemented by two dredgers. The harbour at Coatzaooalcos, as well as that at Salina Cruz, will have a depth of 33 ft. at low water. . At Coatzacoalcos, as at Salina Cruz, elaborate preparations have been made for the expeditious handling of freight. The total frontage of the wharfage will extend 1 kilom. (five-eighths of a mile). There will be eight steel wharves, 136 yards long, and eight iron warehouses, 136 yards long by 36 yards wide, each with a holding-capacity of 6,000 tons; four of these are already completed, and two are under construction. There is also a timber wharf 216 yards long. Each ship loading or unloading will occupy a separate wharf. All the quays are provided with travelling electric cranes of great power, four to each wharf, with a reach from vessels to warehouses or cars of 86 ft., and with numerous capstans. An electric plant of 1,500 kilowatts furnishes the necessary energy for the crane and capstans, and for other purposes Warehouses and cars are equipped with removable roofs to permit the handling of freight in a single operation, working the cranes directly between the vessels and the cars or warehouses. At Salina Cruz, on the Pacific, the engineering problem was much more serious than on the Gulf. The " northers " which sweep across the isthmus beat the surf out to sea, and, since there is no natural shelter, it was necessary to construct both an outer or refuge harbour and an inner harbour with wharves and dry dock. Enormous breakwaters have been built far out into the sea, ending in a depth of 70 ft." with the convex side turned seaward, and form the outer harbour. The entrance to this harbour is 656 ft. across. The east breakwater is 1 kilom. (five-eighths of a mile) long. It extends out for 1,200 ft. in a straight line from the shore, then bends for 825 ft. in a curve witn a radius of about 1,900 ft., and then continues in a straight line for about 1,235 ft. The west breakwater is about 1,900 ft. long, extending in a straight line for 850 ft., and then curving for about 370 ft. on a radius of 325 ft., and continuing in a straight line for 680 ft. The method of construction adopted for the breakwaters is as follows: A rubble foundation is laid up to 33 ft. below low water, 87 yards wide at the base and gradually narrowing to 54 yards at the top. On this foundation huge blocks of concrete or rocks weighing up to 40 tons are dropped at random from steam cranes. Then a smooth surface is made, and on it are placed two rows of concrete blocks of 50 tons weight; they are carefully fitted together and have a joint width of 33 ft. by 6£ ft. high. On the surface thus formed, which is about 18 ft. above low water, a stone parapet will be built 19| ft. wide by 6} ft. high. The outer harbour thus formed covers an area of something like 150 acres. Across the rear of the protected area a line of wharfage extends opening into the interior basin. On this line of wharfage there will be six steel warehouses similar in all respects to those at Coatzaooalcos, equipped with similar electric cranes and capstans, and driven from a generating plant of 1,500 kilowatts. Four of the warehouses are already completed. The inner harbour is the result of dredging, and will eventually be 3,280 ft, long by 925 ft. wide, with a depth of water alongside the wharves of 33 ft. More than half of this inner harbour is now dug out, and for the next two years dredges will be removing the remaining portion of th& basin. The entrance from the outer to the inner harbour will be 100 ft. wide, and will be spanned by two swing bridges. The outer wall of the inner harbour, which is to form the wharves, is a most ingenious bit of engineering. As there was no solid foundation to build on, the following device was adopted. Enormous concrete monoliths, with three large holes, are built on the sand. Through these holes, which are large enough to contain several men, the sand and mud is gradually dug up, partly by suction and partly by manual labour. When the concrete monolith is sunk sufficiently deep another similar section is made in situ upon it, and a similar process is gone through. Before the wharf can be built a foundation of these monoliths will be laid to a depth of 65 ft,, and the holes and interstices filled up with concrete after the monoliths have been sunk to their final destination. The whole will be backed up with masonry and form a wharf 76 yards wide. At both Coatzacoalcos and Salina Cruz, in addition to the berths at the quays, provision has been made for additional slips, and at Salina Cruz one of the finest dry docks in the world, and to-day the largest on the Pacific coast, is being built. This will be 610 ft. by 89 ft., with a depth on sill at low water of 28 ft. The trackage at both Coatzacoalcos and Salina Cruz includes many miles of lines, twenty-six miles at the former and twenty-two miles at the latter port, and the arrangement is such that there can be but little difficulty in handling freight and shunting cars. At Coatzacoalcos an old town already existed, but this is being modernised, with every attention to hygiene. Large offices have been built on the river-bank, and houses have been built on the hill for the staff and employees. The pestilential fever-breeding swamps, which rendered Coatzacoalcos a hotbed of yellow fever and other diseases, have been almost entirely filled in. At Salina Cruz there was nothing but a small Indian village on the site now occupied by the railroad works. A new town has been laid out on higher and more healthy ground, in accordance with modern ideas and sanitary principles, and adequate provision has been made here, as at Rincon Antonio and at Coatzacoalcos, for the comfort and welfare of officers and workmen. It will be seen that preparations have been made for handling this Mexican isthmus route as an essentially transcontinental freight proposition, though the local business, both passenger and freight, is no negligible quantity. When I was on the isthmus the company was handling a large volume of locul freight, and the two passenger-trains it was working seemed to be well filled. However, the principal object of the line is to serve as a connecting-link between ships on the Atlantic and ships on the Pacific, and it is to be anticipated that the principal trans-Atlantic and