In 1802 Fulton’s _Nautilus_, in her trials at Brest, succeeded in blowing up a large boat in the harbour. In 1814 his submersible, the _Mute_, was armed with ‘columbiads,’ or immensely strong under-water guns, which had previously been tried with success on an old hulk. Similar guns were tried nearly fifty years later by the Spanish submarine designer Monturiol. But the offensive weapon of the period was the mine, and the ingenuity of inventors was chiefly directed to methods of affixing it to the side or bottom of the ship to be destroyed. One of these was the use of long gloves of leather or rubber, protruding from the interior of the submarine, invented by Castera in 1827, and adopted by Bauer, Drzewiecki, and Garrett in succession. But the device was both unhandy and dangerous; there would often be great difficulty in manœuvring the boat into a position in which the gloves would be available, and they could not be made thick enough to withstand the pressure of any depth of water. Practical military instinct demanded a method of launching the mine or torpedo against the target, and the first attempts were made by placing a trigger-mine at the end of a spar carried by the nose of the attacking boat. In October, 1863, during the American Civil War, the forts of Charleston were in danger from the accurate fire of the Federal battleship _Ironsides_, and Lieut. Glassell was ordered to attack her in the submarine _David_. He had no difficulty in getting near his enemy and exploding his torpedo, but he had misjudged his distance, and only succeeded in deluging the _Ironsides_ with a column of water. The submarine was herself severely injured by the explosion and had to be abandoned. A second _David_, commanded by Lieut. Dixon, in February, 1864, attacked the _Housatonic_, off the same harbour, and in spite of the greatest vigilance on the part of Admiral Dahlgren’s officers, succeeded in reaching the side of the battleship, where she lay for the space of a minute making sure of her contact. The mine was then fired: the _Housatonic_ rose on a great wave, listed heavily, and sank at once. The _David_, too, disappeared, and it was found three years afterwards that she had been irresistibly sucked into the hole made in her enemy’s side. After this, experiments were made with drifting and towing mines, and with buoyant mines to be released at a depth below the enemy’s keel; but by 1868 the invention of the automobile torpedo by the English engineer, Whitehead, of Fiume, solved the problem of the submarine offensive in the most sudden and conclusive manner.