15. To accompany the scheme of the Maritime Canal, with a scheme for a Canal of communication, of alimentation, and irrigation derived from the Nile, taking its point of departure between the barrage and Boulak, to reach the _Wady_, and come as far as Lake Timsah. The dimensions shall be so calculated, that, taking into account its fall and its supply, the Canal may water at least 100,000 feddans at the time of the inundation, and from 20 to 30,000 during the low water of the river. In the vicinity of Lake Timsah, with which it will communicate, this Canal is to be divided into two branches, for simple irrigation; the first to be directed towards Suez, the other towards Pelusium. 16. To examine whether the sands of the downs on the Isthmus, will occasion any obstacle to the construction and maintenance of the Canal, and how they may be turned to account by means of the Irrigating Canal. 17. To furnish a _maximum_ estimate of the secondary Canal derived from the Nile, and to state the length of time required for the works. 18. To give an account of the nature and quality of the materials, which can be easily, and without great cost of transport, applied in the whole of the works, and also the localities from whence they are to be obtained. 19. Finally, to furnish an approximate statement of the _minimum_ anticipated revenues, of the grand Maritime Canal, and of the Canal of alimentation and interior navigation. I do not mean to confine the labours of MM. Linant _Bey_ and Mougel _Bey_, within the mere limits indicated in this programme. While bearing witness to the good understanding that I have observed to exist between them, and the identity of their convictions, as to the possibility of the communication between the Red Sea and the Mediterranean, by a Canal accessible to large vessels, I beg them, in case the opinion of either, upon any question whatever, should not be entertained by the other, to state the difference of their views, and to assign the reasons thereof. Finally, the precursory scheme, accompanied by an explanatory map, is to be finished as quickly as possible. (Signed) FERD. DE LESSEPS. APPENDIX. No. IV. PRECURSORY SCHEME OF MM. LINANT _BEY_ AND MOUGEL _BEY_, ENGINEERS TO THE VICEROY OF EGYPT. EXTRACT FROM THE MEMORIAL OF MM. LINANT _BEY_ AND MOUGEL _BEY_, ENGINEERS TO THE VICEROY OF EGYPT,[4] By way of Precursory Scheme for cutting through the Isthmus of Suez, by a direct Maritime Canal from Pelusium to Suez.