It was between these new banks that floating dredging-machines of a novel construction, with shoots 220 feet in length, were placed, thus enabling M. de Lesseps to dispense with the previously expensive mode of conveying the silt raised by the dredgers in hopper-barges to sea; the new machines discharged the stuff excavated from the channel over the embankments on to the low and marshy land on either side:[335] by these means two good results were attained; the channel of the canal was economically cleared, and the mud thus excavated employed in greatly strengthening its banks on each side. The cutting of the channel through Birket-el-Ballah, which was more of a swamp than a lake, for a distance of twelve miles, though in itself a very difficult work, was comparatively easy to the excavation of Lake Menzaleh, nor were there any serious obstacles to encounter except in clearing a passage through various mounds of earth extending for a distance of 6 miles, all of which had to be removed or pierced. This difficulty, however, was overcome, after a passage had been cut, by the aid of an ingenious machine called an elevator, which lifted the soil to a height of 56 feet, and carried it along a kind of railed bridge to the places of deposit on either side of the excavated mounds. Eighteen of these elevators, with 700 boxes, were employed on that portion of the works where the banks of the canal were too high to allow the earth cut from the channel to be otherwise disposed of. One of these mounds, that of El Guisr, 61 feet in height, presented a most formidable rampart, which had to be removed in order to allow the waters of the Mediterranean to flow into the vast local depression immediately beyond it known as Lake Timsah, by Ismailia, the interior port of the canal, so named in honour of the Khedive. Here a flourishing new town has been built, surrounded by gardens growing in a fruitful soil, on a site for many centuries a bleak and sterile desert.