At the time Congress voted to adopt a lock canal the estimated cost of a sea-level canal, excluding the cost of sanitation, civil government, the purchase price and interest on the investment (which seem unnecessary refinement in view of later developments) was given by the Board of Consulting Engineers as $247,021,000. The project on which this estimate was made provided for a waterway 40 feet deep at mean sea-level, 150 feet wide at the bottom in earth and 200 feet wide in rock, with a length of 49.14 miles. On the basis of this estimate advocates of the sea-level canal argue that on grounds of economy alone the lock type should be abandoned in favor of the sea-level type. It stands to reason, however, that some of the causes which have led to an increase in cost over the original estimates for the lock canal, such as the increase in the wage scale and the cost of material, and the adoption of the eight-hour day, would affect equally the sea-level project if it were undertaken. The total estimated cost by the present canal commission for completing the work, including purchase price is $375,201,000, while the total estimated cost of the sea-level canal made by the same commission is $563,000,000. This latter sum is largely mere conjecture because of the many unknown elements entering into the problem; and there are successful engineers today who do not hesitate to state that a sea-level canal can be constructed for less than the present lock canal. Very few question the statement that the sea-level canal would take longer for construction than a lock canal. The majority of the Board of Consulting Engineers estimated that from 10 to 13 years would be required. The Isthmian Canal Commission fixed the time at from 18 to 20 years and Lieutenant George W. Goethals, its chairman and chief engineer, states that the lock canal will be completed by January 1, 1915. A great objection to the narrow sea-level canal is the difficulty of river control. The proposed plan was to construct a huge concrete dam 180 feet high across the Chagres at Gamboa. This of itself is a great undertaking but when done would not solve the question of flood control, for below Gamboa there are many more streams which if unregulated would plunge precipitately into the canal channel thereby not only creating cross-currents extremely unfavorable to navigation, and these would also erode the banks and settle deposits which would necessitate continual dredging for maintenance. If these rivers were not allowed to flow into the canal, the only other solution would be the construction of channels on either side of the canal to take care of this flow. This would be very expensive and decidedly dangerous since the rivers in places would be considerably above the canal. The old Chagres Channel and the old French diversion canal could be utilized for a part of the distance.