so numerous
that entrance to the sea on that side may be said correctly to extend
over a stretch of near 400 miles. The islands, it is true, are so many
positions, some better, some worse, from which military effort to
control entrance can be exerted; but their number prevents that
concentration and that certainty of effect which are possible to
adequate force resting upon Gibraltar or Havana.

On the northern side of the sea the case is quite different. From the
western end of Cuba to the eastern end of Puerto Rico extends a
barrier of land for 1200 miles--as against 400 on the east--broken
only by two straits, each fifty miles wide, from side to side of which
a steamer of but moderate power can pass in three or four hours. These
natural conditions, governing the approach to the Isthmus, reproduce
as nearly as possible the strategic effect of Ireland upon Great
Britain. There a land barrier of 300 miles, midway between the
Pentland Firth and the English Channel--centrally situated, that is,
with reference to all the Atlantic approaches to Great Britain--gives
to an adequate navy a unique power to flank and harass either the one
or the other, or both. Existing political conditions and other
circumstances unquestionably modify the importance of these two
barriers, relatively to the countries affected by them. Open
communication with the Atlantic is vital to Great Britain, which the
Isthmus, up to the present time, is not to the United States. There
are, however, varying degrees of importance below that which is vital.
Taking into consideration that of the 1200-mile barrier to the
Caribbean 600 miles is solid in Cuba, that after the 50-mile gap of
the Windward Passage there succeeds 300 miles more of Haiti before the
Mona Passage is reached, it is indisputable that a superior navy,
resting on Santiago de Cuba or Jamaica, could very seriously incommode
all access of the United States to the Caribbean mainland, and
especially to the Isthmus.

In connection with this should be considered also the influence upon
our mercantile and naval communication between the Atlantic and the
Gulf coasts exercised by the peninsula of Florida, and by the
narrowness of the channels separating the latter from the Bahama Banks
and from Cuba. The effect of this long and not very broad strip of
land upon our maritime interests can be realized best by imagining it
wholly removed, or else turned into an island by a practicable channel
crossing