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level of the water of the Gulph to the mean level of the Mediterranean Sea; and this fall, I am decidedly of opin­ion, (if used judiciously), is ample, not only to keep its own channel clear, but also to excavate and maintain a good navigable mouth in the Bay of Tineh, on the shore of the Mediterranean Sea, all the year round. To jus­tify this opinion, I shall endeavour to compare the effects of a salt water channel proceeding direct from Suez to Tineh, and possessing a uniform fall, with the effects of the main branch of the Nile proceeding from Cairo to Bosetta.

We are informed that the half flood of the Nile at Cairo is exactly on a level with the half flood of the sea at Suez; but the distance from Cairo to the Bosetta mouth of the Nile is 125 miles, and from Suez to Tineh 75 miles, while the total fall in both cases being the same, viz. 29*57 English feet, the first would give a de­clivity of 2*838 inches per mile, and the second 4*731 inches. It is, however, to be observed, that the mean height of the tide at Suez is the mean height for the whole year; but the mean state of the flood at Cairo is not so, the duration of the water above half flood being only three months, and consequently the duration below it nine months, giving a farther ratio in favour of the declivity from Suez, or diminishing the average declivity of the Nile for the whole year to 2*4 inches per mile. We have farther to consider that the action of the sea river would be nearly constant, while the action of the Nile would be varying; that the sea river would be of clear water and free from muddy deposits, while the Nile water would be charged with them; that the course of the sea channel would be nearly straight, while the other is crooked; and, lastly, that the sea river