Between Lake Timseh and Port Said, it is estimated that 130,000 cubic yards of sand will be swept into the canal annually. This will give employment for one of the largest dredges for three or four months, working twelve hours each day. This estimate is based on the work done by one of Lavalley’s first-class dredges, which removed 120,000 cubic yards per month, working day and night. But as the material will be distributed in a thin stratum along the entire length of this section of the canal, a longer period will be requisite for its removal. The able engineers who conducted the operations of excavation express confidence in their ability to keep the depth from decreasing. The chief danger from this source, therefore, can only come from a suspension of the work of the dredges. 2. Permanence of the harbors, particularly that of Port Said. The reports of Capt. Spratt, Royal Navy, and of Mr. Mitchell, U. S. Coast Survey, supply very interesting information on this subject. M. Lartet is now publishing, in the _Annales des Sciences Geologiques_, his observations upon the Isthmus. From the map of M. Lartet it appears that an arm of the Gulf of Suez once extended, by the way of the Bitter Lakes, to the Mediterranean, and that, at the same time, the Gulf of Akaba united the waters of the Red Sea and the Dead Sea. The endogenous movement which raised the mountains of Gebel Attaka and the crystalline rocks surrounding the north end of the Red Sea, placed the first barrier between the seas, and, by a succession of seismic movements, raised the cretaceous plateau of Egypt and Syria, or Palestine. The mouth of the Nile at this period must have emptied into the Mediterranean, near the great Pyramid of Gizah; and here the river must have begun to lay the foundation of modern Egypt along the border of the cretaceous formation. Thus the geological record is in harmony with the traditions of the Priests as handed down to us by Herodotus, “Egypt is a gift of the Nile.” Within historic times, the elevating movement has been inappreciable. The Nile still continues to roll down its plenteous bounty of sand, and to spread unceasingly its desolating influence over the plains of Suez and along the coast of Egypt as far as Syria.