38 REPORT OF BOARD OF CONSULTING ENGINEERS, PANAMA CANAL.


were ruin ed, and free exit for the upper waters was permitted through the chamber, the lock alongside would also be emptied and put out of' commission until its neighbor was repaired.
 (7)) The blowing up in a lock of a vessel offered for transit, but designedly laden with high explosives for ignition at the proper moment: In that event the lock would be destroyed, and if it was a lift lock a year or more would be required for repairs.
 (e) The detonation of some high explosive against or under some portion of a dam built to maintain a summit level: This would be a much more difficult undertaking and one less likely to be attempted. The wrecking by explosives of the controlling and discharging sluices in dams would be easier, but a good many men and considerable time f or a successful operation would be necessary. This might be a serious jeopardy at one point for a sea-level canal, but provisional repairs with timber could always be quickly effected.
 (d) The sinking of a large vessel in the canal prism by any means: Recently the steamship Glialkamn, of 2,500 tons displacement, laden in part with blasting gelatin, met with an accident in the Suez Canal and later was sunk. It had to be blown up an-d removed before transit could be resumed. The time during which the canal was closed to vessels was ten days. In case of a similar incident at Panama, whether resulting from an accident as at Suez or from design, the consequences, so ~a as interruption of transit is concerned, might be expected to have a similar result.
 The plan proposed by the Board for the isthmian transit will have twin tidal locks near the Pacific terminus which, if disabled, one or both, as tinder (a), would still be usable (after removal of wreckage) for a part of each day (the period of spring tides) in each lunar month, and probably throughout the whole twenty-four hours during the remainder of the lunar month (neap tides).
 The-.plan also contemplates a damn at Gamboa for Chagres control, provided with regulating sluices. There are to be three small dams for the control of minor streams, but there are to be no lift locks, for these, it is claimed, both single and especially in flight, are much more vulnerable than any other essential accessory that has been proposed to be used hin any type of canal that has been considered by the Board, and this jeopardy is considered to be a very grave one.
 Respecting the liability of the canal to injury and the importance of its defense, the Isthmian Canal Commission in its report dated November 16, 1901, said:
 It is always to be borne in mind that during the excitement of war the canal will not he a safe place for the man-of-war of any nation, no matter who is nominally in control. A small prty of resolute men, armed with a few sticks of dynamite, could temporarily disable it without very great difficulty.
 The Board believes that this jeopardy will exist at all times during the stress of war.
 If an interruption to traffic from any cause should occur while military and naval operations by the United States were in progress, calamitous results would inevitably ensue. If the two belligerents did not include the United States-the custodian of the canal-the closing of the passage might be attempted by one or both the contending powers, and while it would not be done openly, their secret agents would probabl y conspire to its accomplishment. S uch an attempt was feared at Suez while the Russian fleet was passing through that canal en- route to the East, and special precautions to guard against the danger were taken by the canal officials and the Egyptian Governmnent. That the risks would be very much greater for a canal in which lift locks are an essential feature is self-evident, anid in the opinion of the Board such devices should be rigorously excluded from the design of the canal.

 TRANSFORMATION OF A LOCK CANAL INTO A SEA-LEVEL CANAL.

 The instructions of the President to the Consulting Board under date of September 11, 1905, contain the following inquiry:
 I desire also to know whether, if you recommend a high-level mltilock canal, it will be posible after it is completed to turn it into, or to substitute for it, in time, a sea-level canal without interrupting the traffic upon it.
 The Board is of opinion that is is possible to transform a lock canal into a sea-level canal without material interruption of traffic and without serious delays to navigation, although the


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