One of the most persistent workers in this period was a well-known Swedish inventor, Nordenfeldt, who had established for himself a reputation by inventing a gun which even to-day has lost nothing of its fame. In 1881 he became interested in the work which had been done by an English clergyman named Garret. The latter had built a submarine boat which he called the Resurgam (I shall rise)--thus neatly combining a sacred promise with a profane purpose. In 1879 another boat was built by him driven by a steam engine. Nordenfeldt used the fundamental ideas upon which these two boats were based, added to them some improvements of his own as well as some devices which had been used by Bushnell, and finally launched in 1886 his first submarine boat. The government of Greece bought it after some successful trials. Not to be outdone, Greece's old rival, Turkey, immediately ordered two boats for her own navy. Both of these were much larger than the Greek boat and by 1887 they had reached Constantinople in sections where they were to be put together. Only one of them, however, was ever completed. Characteristic Turkish delay intervened. The most typical feature of this boat was the fact that it carried a torpedo tube for Whitehead torpedoes. On the surface of the water this boat proved very efficient, but as an underwater boat it was a dismal failure. More than in any other craft that had ever been built and accepted, the lack of stability was a cause of trouble in the Nordenfeldt II. As soon as any member of the crew moved from one part of the boat to another, she would dip in the direction in which he was moving, and everybody, who could not in time take hold of some part of the boat, came sliding and rolling in the same direction. When finally such a tangle was straightened out, only a few minutes elapsed before somebody else, moving a few steps, would bring about the same deplorable state of affairs. The Nordenfeldt II. acted more like a bucking bronco than a self-respecting submarine boat and as a result it became impossible to find a crew willing to risk their lives in manning her. Before very long she had rusted and rotted to pieces. In spite of this lack of success, Nordenfeldt built a fourth boat which displayed almost as many unfortunate features as her predecessors and soon was discarded and forgotten.
[Illustration: Photo by Bain News Service.
An Anti-Aircraft Outpost.]
In the latter part of the nineteenth century the French Government, which for so many years had shown a strong and continuous interest in the submarine problem, was particularly active. Three different types of boats built in this period under the auspices and with the assistance of the French Government deserve particular attention. The first of these was the Gymnote, planned originally by a well-known French engineer, Dupuy de Lome, whose alert mind also planned an airship and made him a figure in the history of our Panama Canal. He died, however, before his project could be executed. M. Gustave Zédé, a marine engineer and his friend, continued his work after modifying some of his plans. The French Minister of Marine of this period, Admiral Aube who had long been strongly interested in submarines, immediately accepted M. Zédé's design and ordered the boat to be built. As the earliest of successful submarines she merits description:
[Illustration: © U. & U.
A Coast Defense Anti-Aircraft Gun.]
The Gymnote was built of steel in the shape of a cigar. She was 59 feet long, 5 feet 9 inches beam, and 6 feet in diameter, just deep enough to allow a man to stand upright in the interior. The motive power was originally an electro-motor of 55 horse-power, driven from 564 accumulators. It was of extraordinary lightness, weighing only 4410 pounds, and drove the screw at the rate of two thousand revolutions a minute, giving a speed of six knots an hour, its radius of action at this speed being thirty-five miles.
Immersion was accomplished by the introduction of water into three reservoirs, placed one forward, one aft, and one centre. The water was expelled either by means of compressed air or by a rotary pump worked by an electro-motor. Two horizontal rudders steered the boat in the vertical plane and an ordinary rudder steered in the horizontal.
The Gymnote had her first trial on September 4, 1888, and the Paris Temps described the result in the following enthusiastic language:
