A Bavarian by the name of Bauer built a submarine in 1850. Its method of control was by shifting a weight forward to dive and aft to rise. It was a flat-sided and flat-decked vessel with comparatively thin plating and entirely unsuited to resist the pressure of the water at any considerable depth. It collapsed in the harbor of Kiel during one of its trial trips. Bauer kept his presence of mind, however, and when sufficient water had entered and raised the trapped air pressure inside of the boat equal to the pressure outside, he opened the hatch and swam to the surface. This vessel remained partly buried in the mud into which it had sunk until 1887, when it was located during the deepening of Kiel harbor and taken to Berlin, where it is now kept in the Museum of Oceanography as an exhibit of Germany's first submarine. No further important advance was made in the art of submarine navigation until the period of the Civil War, when the Confederates built several small submarines, called "Davids." One of these was called the _Hunley_, after her designer. During her brief career she suffocated or drowned thirty-two men, including her designer. During my early experiments with the _Argonaut_ in 1898 I received a visit from Col. Charles H. Hasker, of Richmond, Virginia, who explained in detail the method of operating the _Hunley_. She was a cylindrical-shaped craft, about thirty feet long and six feet in diameter, with both bow and stern flattened to form a stem and stern-post, respectively. Water-ballast compartments were located in either end of the vessel. She was propelled by eight men, who turned the cranked propeller shaft by hand. These men sat on benches on either side of the shaft. She had the usual vertically hung rudder aft, and a diving rudder forward to incline her bow down for diving, or to raise her bow to bring her to the surface (see page 150). Unfortunately she lacked longitudinal stability, and during her experimental trials twice dove head first into the bottom. Of her experience I have given an account elsewhere. The lesson to be learned from the disastrous trials of this vessel was that sufficient statical stability should always be secured to prevent the vessel taking on an excessive inclination due to shifting of water ballast or movement of crew. [Illustration: THE NEW ORLEANS SUBMARINE Built by the Confederates during the Civil War.] Another submarine built by the Confederates shows a much safer design. It is shown as the New Orleans submarine. According to the story told by a native of New Orleans, this vessel was built during the Civil War to destroy the Northern ships. The story of her launching has been given in a foregoing chapter.