THEEngineer Corps of the United States Army is to be congratulated upon having brought to a success. al conclusion a difficult and unique work of marine cofferdam construction and excavation which, in this particular class of work, is without parallel in the history of engineering. We refer to the successful unwatering of the sunken battleship Maine Sunken vessels have been recovered in various ways, but never, so far as we know, has a ship lying on the bottom been salved from the water by the method adopted in the case in question. The recovery of a ship of six or seven thousand tons displacement, lying in 37 feet of water upon a bed of mud and soft clay of approximately equal depth, is a problem of considerable magnitude, even - when the hull of the ship is in an approximately sound condition ; but when, as in the case of the “Maine,” the forward third of the vessel has been blown entirely to pieces, the difficulty is many times multiplied. When the army engineers received instructions to recover the “Maine” so that every part of the ship could be subjected to' a thorough examination, they were confronted with a problem which they might well have pronounced impossible of solution. The. plan adopted of building entirely around the wreck a massive cofferdam wall extending from solid bottom to several feet above high water mark, was the subject of much criticism from the day the plans were first made public. Complete failure of the cofferdam was freely predicted by the engineering profession. Yet in spite of the difficulties due to the tendency of the mud-filled wall to leak and to yield by distortion, the fact remains that it has done ii work, and that the army engineers have so far lai bare the wreck that not only will the after two-thirc of the ship be floated and towed away to be sunk, ..s sea, but practically every part of the wrecked p tion of the structure has been made to yield its quo,t of evidence in determining the first cause of tl disaster. The joint army and navy board appointed bj tj Secretary of the Navy has presented its report, ai an advance official statement has been given out ; Washington which says, “The board finds that the 1 juries to the bottom of the “Maine” were caused l the explosion of a charge of a low form of explosi exterior to the ship between frames Nos. 28 and 3 strake B, port side. This resulted in igniting ai exploding the contents of the 6-inch reserve ma, azine, A-14-M, said contents including a large qua tity of black powder. The more or less complete i plosion of the contents of the remaining forward ma azine followed. The magazine explosions resulted the destruction of the vessel." The investigation disclosed the fact that there is fracture some 20 feet wide extending across the botto of the vessel at a point about 100 feet from the bo' From the fact that the frames were still in positio though, of course, much distorted, the board conclud that a low form of explosive was used in destroy!, the vessel. A high explosive would have cause'J much more complete destruction of the material in ' immediate vicinity. Incidentally, the report sustai] the findings of the Sampson board, which investigate 1 MERICAN 579 the disaster in 1898, immediately after the 'Maine' was blown up. That board located the point of the exterior explosion at about frame 18 on the port side, but its report was based upon an examination by Civers working in 37 feet of water. The unwatering of the “Maine” has made possible a closer approximation to the truth and it is now disclosed that the point at which the vessel was ruptured lies between frames 28 and 31, The after portion of the hull remains practically intact. Forward of frame 30 is a gap of about 20 feet, where the ship. was cut in two, and forward of the confused wreckage lies the bow, which was blown entirely out of position, swung around to starboard, and broken off from the ship's structure at frame 14. The stem of the vessel, instead of being in the vertical position, now lies horizontally and at right angles to the keel of the vessel, a considerable section of the plating on the port side being still attached to the stem. A long strip of the double bottom lies on the top of the after edge of the severed bow, and beneath this severed portion rests a section of the keel some ten feet in length. One end of it lies in the mud, and the other end, twisted backward and upward, is now resting against the shell of the detached section of double bottom. In places the keel has been turned entirely upside down, so that some sections of the bottom plating are uppermost. The sequence of events on the night of the disaster is now clear. A charge of low explosive, probably a large quantity, was set off below the bottom of the “Maine,” forward of frame No. 30 on the port side, and a few feet from the keel. How this destructive agent was contained, at what depth it was located, and how it was set off, will probably never be known. Whether the mine was touching the ship or on the harbor bottom, the force of the explosion would seek the line of least resistance, which would lie vertically through the body of the ship, The rush of gases tore through the double bottom and the shock and heat of the explosion set off the black powder, of which there was a considerable amount in the magazine just above the point of explosion, and this, in turn, ignited the forward magazines. The enormous energy thus liberated, having the water below and on the sides of the hull as an abutment, expended its energy in tearing asunder and folding back the overlying protective and other decks of the ship. The illustrations which were published showing the recent wreck of the French battleship “Liberte” were strongly suggestive of similar illustrations of the wreck of the “Maine,” published shortly after the event. The whole structure of the “Liberte” in the region of the explosion was opened out and folded back by the explosion of the magazines, presenting an appearance remarkably like that of the disaster in Havana Harbor. In the case of the “Maine” the magazines were set off by an exterior explosion, whereas on the “Liberte” the explosion was due to the deterioration and spontaneous ignition of the smokeless powder, It should be noted that outside of a comparatively small amount of ammunition for small arms, there was no smokeless powder on board the “Maine” at the time of the disaster.