While discoverers and inventors were directing their attention to these intentionally destructive contrivances, the principal governments were cautiously testing some of them as opportunity offered. The Russians studded the Baltic with submerged torpedoes in 1854-55; iron cases containing combustibles, sulphuric acid, and chlorate of potash, so placed that a sudden concussion would make the whole explode. Very few British ships were really hit by them; but a good deal of uneasiness was felt by the crews of Admiral Sir Charles Napier's fleet, who would much rather have encountered an open enemy than a concealed submarine foe, the whereabouts of which could not be determined beforehand. In 1866 the Austrians in their brief war with Italy used torpedoes in which gun-cotton was fired off by an electric current. During the American Civil War, 1861 to 1865, nearly forty vessels were destroyed by torpedoes. (We may here mention that this name, first given to these contrivances by the Americans, was derived from one designation of the torpedo or electrical fish.) Three-fourths of the destruction was wrought by the Confederates against Federal vessels, but the remainder blew up or disabled the Confederates' own ships. The torpedoes employed were of various kinds and sizes, some exploding by mechanical concussion, some by chemical action, some by electric discharge. One of them was a complete submarine boat, which could be lowered to several feet below the surface of the water, and there propelled with hand-paddles at the rate of four miles an hour, by men shut up in a water-tight compartment, and provided with half an hour's compressed fresh air. This submarine boat dragged a floating torpedo, allowed it to come under the bottom of an enemy's ship, paddled away to a safe distance, and then fired the torpedo by an electric fuse. Such at least was the theory; but it proved to be a case of the engineer 'hoist by his own petard;' for although the torpedo really did destroy a Federal ship, the submarine boat and its crew were never afterwards seen or heard of.[A]