ENGINEERING. 



279 



European diplomacy delayed for twenty years. 

 The same year witnessed the indefinite post- 

 ponement, from political motives equally false 

 and retrograde, of another work of even bolder 

 design, and of scarcely less importance to civ- 

 ilization, which engineering art stands ready 

 to execute. (See ENGLISH CHANNEL TUNNEL 

 PANIC.) 



Among the ship-canals under discussion are 

 one from Bordeaux to Narbonne to join the 

 Atlantic and Mediterranean, one to connect 

 the North Sea and the Baltic, the Nicaragua 

 maritime canal, one through the Isthmus of 

 Kraw, and the recently projected Manchester 

 ship-canal. The protests of De Lesseps against 

 the violation of the Suez Canal by the British 

 army led to the discussion of a new canal be- 

 tween the Mediterranean and the Eed Sea. 

 As the concession to the Suez Company con- 

 veys the exclusive right to the isthmus route, 

 the construction of a ship-canal from Alexan- 

 dria to Suez by way of Cairo was proposed. 

 The Suez Canal is insufficient for the present 

 traffic, and will have to be enlarged if a second 

 canal is not constructed. The proposed canal 

 through the Delta would be of great value to 

 the irrigation system of Egypt, as it would be 

 a sweet-water canal, fed from the Nile. The 

 quantity of material to be excavated would be 

 about 160,000,000 cubic yards, or double the 

 quantity removed in the construction of the 

 Suez Canal. The drainage-canals constructed 

 by Ismail Pasha in the first ten years of his 

 reign involved an equal amount of excavation. 

 To efficiently irrigate the lands of the Delta it 

 is found that about an average of seven tons 

 of water per day are required for every acre. 

 This, for the total area of 3,000,000 acres, 

 would call for a constant supply of 250 tons 

 per second, which is five sixths of the discharge 

 of the river at lowest Nile. The Menoufieh 

 and the Behera Canals are capacious enough 

 to convey the whole quantity of water needed, 

 but they carry off together not more than sev- 

 enteen tons of water per second when the river 

 is at its lowest stage. The present drainage 

 system is constructed so as to keep the water 

 stored in reservoirs formed by sluices in the 

 canals. The removal of the sediment which 

 settles in these reservoirs involves an enor- 

 mous amount of labor. The proposed canal 

 to Cairo and Suez would be able to supply 

 the entire 250 tons per second without inter- 

 fering with its function as a ship-canal. Half 

 the surface of the Delta could be directly irri- 

 gated from the canal, and the other half, com- 

 prising the lands between the Rosetta and Da- 

 mietta branches, could be supplied by means 

 of large siphons or by reconstructing the bar- 

 rage of Mehemet Ali. 



The final surveys for the Panama Canal have 

 been completed, and the work is advancing at 

 Colon, Gorgona, Bas-Obispo, Emperador, Cu- 

 lebra, and Paraiso. Very heavy dredgers have 

 been brought from Philadelphia, and a large 

 quantity of other machinery will be employed. 



As the work progresses the belief is confirmed 

 that less rock excavation will be necessary than 

 was calculated. 



Rapid progress has been made on the Isth- 

 mus of Corinth Canal. The material to be ex- 

 cavated is alluvial earth, so that about 300,000 

 cubic yards can be removed per month by the 

 aid of the Priestman excavating machine and 

 with dredgers. The total amount of excava- 

 tion to be done is estimated at 13,000,000 cubic 

 yards, 1,000,000 of which is dredging, 1,700,000 

 mixed earth and rock, and 1,000,000 rock below 

 water. 



The important Sirhind drainage-canal in the 

 Punjaub, in British India, was completed with- 

 in the year. The canal is 500 miles in length. 

 It has subsidiary trenches of about 5,000 miles 

 in aggregate length. It draws its water from 

 the Sutlej, and distributes it over 750,000 acres 

 of land. 



The docks at Milford Haven, in South Wales, 

 are nearly completed. A fleet of fast mail- 

 steamships has been projected in the United 

 States, which will make the voyage from New 

 York to Milford in six days, and there connect 

 with a special train to London, on the Great 

 Western Railway. Milford Haven is the finest 

 natural harbor in England, being the largest, 

 the most sheltered, and the easiest of access ; 

 yet, since it was deserted by the Royal Navy- 

 Yard and the Irish Steamship Line, it has had 

 no commerce until it was taken hold of by the 

 company which has been improving its harbor 

 facilities and railroad connections for the last 

 six or seven years. Vessels need no pilot, as 

 the entrance is nearly two miles wide. The 

 harbor is virtually landlocked, and has a mini- 

 mum depth of eight fathoms. The new docks 

 have an area of sixty acres. The entrance- 

 lock is 500 feet long by 70 wide. The graving 

 dock, which can also be used as a wet dock, is 

 710 feet in length and 96 in width. There is a 

 small graving dock 270 by 46 feet. The depth 

 over the sills at high water in the spring-tide 

 is 36 feet, in the neap-tide 27 feet. The docks 

 were made by closing the mouth of a creek 

 with a wall and caissons, and dredging out the 

 inclosed area. There are two locks to the dock, 

 so that a vessel can be put upon the dry dock 

 immediately upon coming in from sea. Both 

 ends of the great dock and the entrance to the 

 graving dock are closed by caissons of novel 

 design. The end of the graving dock which 

 opens into the wet dock, is shut by a floating 

 caisson of the common type. The new cais- 

 sons rise, when the water is removed from the 

 flotation chambers, about nine inches above 

 the floor between the sills, and pass into lateral 

 chambers, their motion being controlled by a 

 valve which closes a culvert, and by rollers on 

 top running on girders extended over the re- 

 ceiving chambers. Tb.e weights of the lock 

 are 250 tons, and those of the graving dock 300 

 and 400 tons respectively. To remove the salt 

 water from the large caisson which was used in 

 putting in the sill of the graving dock at every 



