ilding of submarines. Most of her boats are of
the Laurenti type--which is a very close adaptation of the Lake
type. Russia and Japan, especially the latter, built up fairly
efficient underwater fleets. The lesser countries, like Austria,
Holland, Sweden, Denmark, Norway, and Spain have concerned
themselves seriously with the creation of submarine fleets. The
submarine boats of all of these countries in most instances were
either of the Lake or Holland type though frequently they were built
from plans of English, French or German adaptations rather than in
accordance with the original American plans.

The exact number of submarines possessed now by the various navies
of the world is a matter of rather indefinite knowledge. Great
secrecy has been maintained by every country in this respect. From a
variety of sources, however, it has been possible to compile the
following list which at least gives an approximate idea of the
respective strength of the various submarine fleets at the beginning
of the war. The numbers assigned to each country are only
approximate, however, and include both boats then in existence or
ordered built: United States 57; Great Britain 104; France 92;
Germany 36; Italy 28; Russia 40; Japan 15; Austria 12; Holland 13;
Denmark 15; Sweden 13; Norway 4; Greece 2; Turkey 2; Brazil 3; Peru
2.

Having traced the development of the submarine from its earliest
beginnings to recent times we are naturally now confronted with the
question "What are the principal requirements and characteristics of
the modern submarine?"

The submarine boat of to-day, in order to do its work promptly and
efficiently, must first of all possess seaworthiness. This means
that no matter whether the sea is quiet or rough the submarine must
be able to execute its operations with a fair degree of accuracy and
promptness and must also be capable of making continuous headway.
Surface and underwater navigation must be possible with equal
facility and it is necessary that a state of submergence can be
reached without loss of time and without any degree of danger to the
boat's safety. At all times, travelling above water or below, the
submarine must possess mechanical means which will make it possible
to control its evolutions under all conditions. Furthermore, the
ability of the submarine to find and to observe objects in its
vicinity must not be greatly reduced when it is in a submerged
position. In the latter it also becomes of ext