As for the cost, that has always been an unknown quantity, and, I think, has always been a secondary consideration. The fear of undue delay seems to have been the principal deciding factor in favour of the high-level scheme. Rival expert opinions that the majority of the Board of Engineers had under-estimated the time required for the tide-level canal were adopted by those in authority, and mainly on this account, I think, the high-level scheme became law. Since visiting the Isthmus a second time, and inspecting the work in the great Cut between Empire and Paraiso, it has seemed to me that there is an objection to the tide-level project which did not fully appear in the early stages of the work, viz., that the behaviour of the rock might involve the engineers in ever-increasing difficulties as the depths increased. The opinion which had been held by many that the difficulties would diminish with the depth did not seem to me to be justified up to that time. [Illustration: LIDGERWOOD UNLOADER, WINDING APPARATUS.] [Illustration: _ANOPHELES_ BRIGADE OILING A DITCH.] Next let us see what are the special difficulties of the high-level project. This also depends for its success mainly on the efficacy of one dam, which is now being made at Gatun. It will hold up the waters not only of the Chagres but of its tributaries, to a level of 85 feet above mean tide, and the area of the lake thus to be formed is shown on the map. The Chagres will be ponded back far above the point where it enters the Canal, and thus will be effectually tamed. The flood-waters will be spread over an area of about 164 square miles--for Lake Gatun will be twice the size of Lago Maggiore and about four-fifths that of the Lake of Geneva,[9] and ships, in the ample waterway, will not be troubled by currents. [9] The size, in fact, will not differ greatly from that of the principal basin of the Lake of Geneva, all above the _petit lac_, or narrow part at the Geneva end. A good idea of this area is obtained by recalling the well-known view over the waters of this lake from the _quai_ at Ouchy. A flight of three locks at Gatun will raise ships to the level of this lake in coming from the Atlantic, and one lock at Pedro Miguel and two at Milaflores will lower them to the level of the Pacific. It has been claimed that if the Gatun dam burst the consequences would be less disastrous than if the Gamboa dam burst, but there is in reality little to choose between the two catastrophes.