1915] SUBMARINE BOATS 121 
boat up to that time, but the speed was too slow, the radius of action 
small, and steering in the vertical plane remained an unsolved problem. 
The boat, therefore, had no military value and in 1874, after ten years 
of experiments, the French Government abandoned the project. 
THE PERIOD FROM 1880 TO 1905. 
The greatest difficulty before the designers of submarine boats 
prior to 1880 was to find a source of power suitable for underwater 
propulsion. Compressed air, tried in the Plongeur, was probably the 
best available means of storing energy for that purpose, but the air 
reservoirs occupied too much space, whence the supply of energy that 
could be carried was too limited. It was, therefore, of the greatest 
importance for the solution of this problem when in 1880 the French 
scientist Faure succeeded in improving the lead accumulator, invented 
by Planté in 1859, by applying a layer of red lead paste as an active 
material to the lead plates. The accumulator so perfected afforded a 
means of storing energy eminently adapted for submarine boats since 
it was independent of the atmospheric air and, although heavy, took up 
relatively little space. 
Another difficulty was that no weapon existed, suitable for a sub- 
marine boat. Neither the attachment of mines to the bottom of an 
enemy’s ship, or the use of spar or towing torpedoes offered satisfactory 
solutions, and ramming was at least as dangerous to the submarine 
boat as to the enemy’s ship. Another great step in advance was, there- 
fore, made when the Whitehead torpedo appeared about the end of 
the ‘‘seventies’’. This weapon enabled the submarine boat to attack a 
ship from a distance without difficult and dangerous manceuvyres. 
At the same time there was in the “‘eighties’”’ a strong development in 
all machinery and fittings used in the application of electric power and 
light, and great progress was made in the production and storage of 
compressed air. 
Thanks to all these inventions and to the general rapid advance in 
all fields of engineering which was characteristic of that period, the 
problem of the submarine boat suddenly became capable of a practical 
solution. In various parts of the world designs were prepared and ex- 
perimental boats were constructed, which before the end of the century 
led to the production of boats practically applicable in naval warfare. 
In the “eighties” the author of this article commenced to study the 
problem* and worked out several designs of which that of a ‘‘diving 
boat’’ published in 18887 will be here briefly described in order to 
*Submarine Boats, London, 1887. 
aa Proposed Designs for Surface Boats and Diviwg Boats, Institution of Naval Architects, London, 
