Porto Rico, which
boasts 264 inhabitants to the square mile. In the smaller area of the
Danish Indies and Guadeloupe about this same density (215 and 274)
reappears; but it mounts to 470 in Martinique and to 1160 in
Barbadoes.[954]

[Sidenote: Island resorts.]

Climate advantages often encourage density of population on islands, by
attracting to them visitors who make a local demand for the fruits of
the soil and thereby swell the income of the islands. For instance,
about the densely populated region of the Gulf of Naples, Procida has
14,000 inhabitants on its one and a half square miles of area, while
fertile Ischia and Capri have 1400 to the square mile. Here a rich
volcanic soil, peaks which attract rain by their altitude and visitors
by their beauty, and a mild oceanic climate delightful in winter as in
summer, all contribute to density of population. Sicily, Malta and Corfu
also gain in the same way in winter. The Isle of Man owes some of its
recent increase of population, now 238 to the square mile, to the fact
that it has become the summer playground for the numerous factory
workers of Lancashire in England.

[Sidenote: Density of population affected by focal location for trade.]

Sometimes climatic advantages are reinforced by a favorable focal point,
which brings the profits of trade to supplement those of agriculture.
This factor of distributing and exporting center has undoubtedly
contributed to the prosperity and population of Reunion, Mahe, Mauritius
and Zanzibar, as it did formerly to that of ancient Rhodes and modern
St. Thomas at the angle of the Antilles. Barbadoes, by reason of its
outpost location to the east of the Windward Isles, is the first to
catch incoming vessels from England, and is therefore a focus of
steamship lines and a distributing point for the southern archipelago,
so that we find here the greatest density of any island in the West
Indies.[955] The 9405 inhabitants of Charlotte Amalie on St. Thomas and
the 15,000 of Willemsted on Curacao give these also a characteristic
insular density. Samos, blessed with good soil, an excellent position on
Aegean maritime routes, and virtual autonomy, supports a population of
300 to the square mile.[956]

Focal location alone can often achieve this density. Syros, one of the
smallest and by nature the most barren of the Cyclades, though well
tilled is the great commercial and shipping center of the Aegean, and
has in Hermupolis with its 17,700