124 TRANSACTIONS OF THE ROYAL CANADIAN INSTITUTE [VOr.) xe 
and the previous spindle-shaped boats built by the French Government 
which he called “sous-marins”. The hull is double, consisting of an 
inner spindle-shaped ‘strength hull’’ of heavy construction, calculated 
to resist the maximum pressures of the water, and a light outer ship- 
shaped hull which completely envelops the inner. The shape of the 
aft-body resembles that of a Thornycroft torpedo boat. The space 
between the two hulls is used chiefly for water ballast, whence a very 
great reserve buoyancy may be obtained. It was found difficult at 
first to fill the tanks in a complete manner; whence shifting of air- 
bubbles were apt to cause violent changes in the longitudinal balance 
of the boat, and the vertical steering was disturbed. Also the filling 
of the tanks took nearly one-half hour, much too long for immersing 
the boat when in the presence of an enemy. These defects were 
afterwards remedied in the Narval and were avoided in later boats of 
this type. The Narval was driven by steam in the surface, where she 
made 12 kts. The boilers used oil-fuel. Under water she was driven 
by electric power and attained a speed of 8 kts. She carried four 
18-in. torpedo tubes. The heat from the machinery caused considerable 
trouble. On the whole, however, the Narval proved satisfactory and 
was the type ship for a great number of following boats. Other types 
of submersibles which have later been developed, such as the Germania 
and the Laurenti types, are derived from the Laubeuf boats. 
In the United States Mr. John P. Holland worked with great per- 
severance for a number of years and built several experimental boats. 
The first, which was very primitive, being worked by hand-power, was 
launched in 1878. Finally, through the agency of the Holland Torpedo 
Boat Company, he succeeded in producing a boat that was accepted 
by the United States Navy in 1899. The boat, which was named the 
Holland, was $4 tons; it was cigar-shaped with but a small superstructure 
on the top and, consequently, had very little stability in the surface 
condition. The reason of the success of this boat was the use of a gaso- 
line engine for surface work, combined with a storage battery for the 
submerged condition. Holland first tried steam-power but failed, and 
the gasoline motor which had just then been developed to a practicable 
shape was here used for the first time in submarine boats. The gasoline 
engine had several great advantages; it occupied relatively small space 
and did not produce so much heat as a boiler and steam engine; it con- 
sumed very little fuel so that a great radius of action could be obtained. 
The engine of the Holland was of 50 H.P. and gave the boat a speed of 
8 kts. on the surface. The electric motor was of about the same power 
and drove the boat with a speed of 6 kts. under water. A novelty in 
this boat was the way in which diving was effected. Contrary to earlier 
