The construction of torpedo boats for harbor defense was no longer a novelty, but this was the first attempt made to demonstrate that a submarine torpedo vessel could be used on the high seas to overtake and destroy a flying enemy. The _Etna_ and the _Stromboli_ each carried one hundred shells, each shell being loaded with five hundred pounds of potentite. Chain cradles for holding these shells were suspended to huge fans of finely-tempered steel, shaped like pincers, and the machinery for fastening one or more of these cradles to the bottom of the vessel it was intended to destroy was both simple and ingenious, as were the arrangements for exploding them when fastened. A fuse or wire attached to a steamer running away at the rate of a mile in three minutes would have been impracticable, and the inventor had therefore arranged a time or clockwork cap, which could be set to explode at any given number of minutes from the time the shell should be fastened. The _Siva_, containing Mr. Morning, the foreign engineers, and the ordnance officers of the American Navy detailed for the service, left her moorings at nine o’clock and steamed down the bay, followed by the _Warspite_, flying the British flag, the French corvette _Garronne_, the Russian frigate _Tsar_, the Italian ironclad _Victor Emanuel_, the Spanish ship _Pizarro_, the Chilean man-of-war _Cero del Pasco_, the Swedish sloop-of-war _Berdanotte_, the American iron batteries _Charleston_ and _San Francisco_, and the great German steel war ship _Wilhelm II._ It was intended that this latter vessel should follow the _Warspite_, but there was some delay in getting her under way, and she was the last in the naval procession, being followed only by the _Esmeralda_—the vessel to be destroyed. At the termination of the Chilean insurrection it was found that the _Esmeralda_—the war ship controlled by the insurgents—was, though not unseaworthy, yet too badly damaged by a contest with gunboats to be serviceable for the purposes for which she was constructed, and she was, therefore, sold by the Chilean Government to Mr. Morning for $1,000,000—something less than one-third her cost. He purchased her for use as a transport in connection with the construction of the Nicaragua Canal, in which he was interested, and he now devoted her to destruction, as a test of the power of the new explosive, and the efficiency of the submarine torpedo boats. The _Esmeralda_ was an ironclad steamer of the largest size, capable of a speed of twenty miles an hour. She was armored with steel plates, and in every way staunch. On this occasion she carried only sufficient force to navigate her, and she towed a large steam launch, into which her crew would be transferred and conveyed to a place of safety so soon as the torpedoes should be fastened to her. Two lifeboats were also swung, ready for launching in case of accident.