icanes are felt only on the north coast, at
others on the south coast, although generally their influence extends
throughout the island.

In 1825 a hurricane destroyed the towns of Patillas, Maunabo, Yabucoa,
Humacao, Gurabo, and Caguas, causing much damage in other towns in
the east, north, and center of the island. The island was also visited
by a terrible hurricane in 1772.

Earthquakes.--Earthquakes are somewhat frequent, but not violent or
of great consequence. The natives foretell them by noticing clouds
settle near the ground for some time in the open places among the
mountains. The water of the springs emits a sulphurous odor or leaves
a strange taste in the mouth; birds gather in large flocks and fly
about uttering shriller cries than usual; cattle bellow and horses
neigh, etc. A few hours beforehand the air becomes calm and dimmed by
vapors which arise from the ground, and a few moments before there is a
slight breeze, followed at intervals of two or three minutes by a deep
rumbling noise, accompanied by a sudden gust of wind, which are the
forerunners of the vibration, the latter following immediately. These
shocks are sometimes violent and are usually repeated, but owing to
the special construction of the houses, they cause no damage.

Tides.--For seven hours the tide runs rapidly in a northwest direction,
returning in the opposite direction with equal rapidity for five hours.

Orography.--The general relief of Porto Rico is much inferior in
altitude to that of the rest of the Great Antilles, and even some of
the Lesser Antilles have mountain summits which rival it.

A great chain of mountains divides the islands into two parts, northern
and southern, which are called by the natives Banda del Norte and
Banda del Sur. This chain sends out long ramifications toward the
coasts, the interstices of which form beautiful and fertile valleys,
composed in the high parts of white and red earths, on the spurs of
black and weaker earths, and near the coasts of sand.

To the northwest and following a direction almost parallel with the
northern coast, the Sierra of Lares extends from Aguadilla to the
town of Lares, where it divides into two branches, one going north
nearly to the coast, near Arecibo harbor, and the other extending
to the spurs of the Sierra Grande de Banos; this latter starting
from Point Guaniquilla, crosses the island in its entire length,
its last third forming the Sierra of Cayey.

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