From this period, to the beginning of the present century, save for half-hearted projects of the Venetians, and, later, of the Porte itself, we hear no more of the question till Napoleon invaded Egypt, and ordered an immediate survey of the isthmus with a view to the establishment of a maritime canal.[142] Napoleon was himself no mean engineer, and he employed on this work a man who seems to have possessed a remarkable grasp of the problem presented for solution, but who, nevertheless, shared the then common impression that the Red Sea was at a higher level than the Mediterranean, and that to join the waters of the two seas would be to submerge a great part of the country. This man was M. Lépère. He made a survey of the route between the two seas, and declared that he had found the Red Sea to be 30 feet above the Mediterranean.[143] When Napoleon Buonaparte, at the time of the French expedition to Egypt, ordered a complete survey to be made of the isthmus between the Mediterranean and the Red Sea by M. Lépère, the latter proposed that vessels should ascend the Nile to Bubastis, and pass by a canal, 18 feet deep and 77 miles long, to the basin of the Bitter Lakes. Thence, a second canal, 13 miles in length, was to lead to the Red Sea. The cost of this undertaking was calculated at 691,000_l._, but additional works in the mouth and bed of the Nile, and the restoration of the canals of Faroumah, Chebri-el-Koum, and Alexandria, was estimated to raise the cost to 1,200,000_l._ Surveys of the country were afterwards made by Captain Chesney, in 1830, and by Mr. Robert Stephenson in 1847, with a view to the opening up of a waterway between the two seas. Captain Chesney reported on the Isthmus of Suez as offering great facilities for the construction of a canal. “There are,” he said, “no serious difficulties; not a mountain intervenes, scarcely what deserves to be called a hillock.” Stephenson, however, who personally examined the ground, considered that any canal made across the isthmus should be provided with locks, as the absence of current would otherwise allow of silting. Admiral Spratt, ten years later, came to the same conclusion as Stephenson, but both were opposed by M. de Lesseps, who, in his final plan, resolved upon a dead level canal for the whole distance of 103 miles. The plan ultimately adopted has no doubt been the most advantageous to commerce, inasmuch as it has facilitated the time and labour involved in passing vessels through the canal. It has, however, necessitated a considerable annual outlay for dredging. Nearly two millions of cubic yards of material have had to be removed in a single year from the bed of the canal, in order to maintain the requisite depth.