40 ANNUAL OF SCIENTIFIC DISCOVERY. 



of the ship canal, however, from Port Said to Tsmailia is suf- 

 ficiently advanced to allow the passage of boats drawing 5 feet 

 of water. 



The whole extent of the isthmus is covered witli marine shells, 

 similar to those now found in the neio-hborino^ seas, indicatino: 

 that at a comparatively recent geological period the salt water 

 stood at a higher level than it now does, and that the isthmus, as 

 such, did not then exist. There is a remarkable depression in this 

 neck of land, as now seen, and through this depression or valley- 

 tlie canal will be constructed. Port Said is in latitude 31° 16' N., 

 longitude 32°, 19' E. This point was selected because the line of 

 33 ieet soundings was nearer to the beach than elsewhere 

 along the coast, being only about 2 miles from the shore. The 

 beach, in all this region, is merely a narrow strip of sand, 1 or 

 200 yards wide, inside of which are numerous shallow lakes, or 

 mere salt marshes, some of great extent. 



Through one of these shallow lakes, called Menzaleh, the canal 

 will be dug for nearly 30 miles ; at the end of this is Lake Ballah, 

 about 8 miles in extent as crossed by the canal, and at the south- 

 ern side of this is the highest point of land in the whole line. The 

 extreme width of this ridge, called El Guisr, is about 10 miles, 

 with a summit 61 feet above the sea level, which, added to 26 

 feet, the depth of the canal, will require a cutting of 87 feet. On 

 the southern side of El Guisr is Lake Tirasah, through which the 

 canal will be dredged for about 5 miles ; it then crosses the ridge 

 of Serapeum, about 8 miles in width, with a maximum cut of 61 

 feet. After this, proceeding southward, the line strikes the im- 

 mense basin of the Bitter Lakes, where the level is, in many 

 places, as great as will be required, and where comparatively 

 little work will have to be done for 23 miles. This depression 

 is bounded on the south by the ridge of Chalouf, about 5 miles 

 wide, where there must be a cutting 55 feet deep for a short 

 distance. Between Chalouf and the Red Sea is the plain of Suez, 

 10 miles in extent, as crossed by the canal, and elevated only a 

 few feet above the sea level. 



The construction of the entrance to the canal at the Suez end 

 presents no great engineering obstacle ; the head of the Red Sea 

 is so completely land-locked as never to be troubled with a very 

 heavy swell, and there is no current at all ; so that it will only be 

 necessary to dredge out a channel into deep water. 



At Port Said there will be more difficulty ; the harbor there will 

 be formed of 2 jetties or piers, the western one extending into 

 the sea about 2h miles in a north-north-east direction ; the other 

 pier will extend a little more than 1^ miles in a direction nearly 

 north ; a triangular area of 575 acres between the two, forming 

 an outer harbor, will be dredged to a depth of 30 feet. 



The piers were commenced with stone, but are now constructed 

 of a concrete made of h3'draulic lime from France and the sand 

 in the harbor, about 715 pounds of lime to 37 cubic feet of sand; 

 after having been submerged a few months the concrete becomes 

 nearly as hard as granite ; the interstices are filled by sand brought 

 by the current from the west, thus forming a solid mass, which 



