4th. The direct track is the most useful. It serves at the same time the interests of commerce in general and the political interests of Egypt and the Ottoman Empire. It will require but little to maintain it, and as there will be very few works of art, navigation will not be exposed to those interruptions which it would have to dread on the indirect track. To these evident advantages of the direct track, to these relative facilities which had attracted the attention of the sovereigns of Egypt, of Amrou and Mustapha III. for example (see Lebeau, _Histoire du Bas-Empire_, tom. XII. p. 490, and the _Mémoires du Baron de Tott sur les Turcs_, pts. III. and IV.), before attracting that of the nineteenth century, there is but one objection, and it is this:— It is impossible, they say, for large ships to approach Pelusium; and the direct Canal is chimerical, because it cannot open into the Mediterranean. This oft-repeated objection is but specious, and cannot stand before an examination of the facts. The entrance to Pelusium is certainly a difficult and costly work, but it is perfectly practicable, and engineers have overcome very different obstacles with resources much inferior to those now at their command. It is well in the first place that it should be known that the level of the two Seas, excepting the difference of the tides, which are pretty high at the south in the Red Sea, and almost nothing at the north in the Mediterranean, is perceptibly the same. The commission of 1799 had found for the Arabian Gulf an elevation of 9 _met._ 90; but its labours, performed in the midst of all the dangers and disturbances of war, had not been verified, and the genius of Laplace resting upon accurate theoretical views, had formally denied the possibility of such a depression within a distance of scarcely thirty leagues. Afterwards, towards 1840, some English officers had proved by the barometer and the boiling water process that there was no difference of level; and in 1843, Prince Metternich, having been informed of these labours, sent instructions to Egypt to induce Mehemet Ali to interest himself in the grand undertaking of the cutting of the Isthmus: his dispatch is still in the Archives of the Austrian Consulate at Alexandria. In 1847 a commission of French engineers, sent out by M. Paulin Talabot under the direction of the learned M. Bourdaloue, and assisted by Egyptian engineers directed by M. Linant, chief engineer to the Viceroy, put the fact beyond all question, and M. Paulin Talabot had the honour of stating it in a memorial that has become famous. Our Academy of Sciences bestirred itself for the honour of the ancient Egyptian commission. M. Sabatier, Consul general of France, asked the Viceroy for a fresh verification, which M. Linant was charged to undertake in 1853, and which confirmed, saying an insignificant variation, the labours of 1847.