The space included between the Sulu Archipelago to the south and Mindoro to the north, and having the Philippine Islands on the east and Palawan on the west, is distinguished by the name of the Sulu Sea.  Although of great depth, 2,550 fathoms, this sea, which is in connection with the China and Celebes seas, and also with the Pacific by San Bernardino and Surigao straits, has a minimum deep-sea temperature of 50.5 degrees, reached invariably at 400 fathoms.  As this temperature in the China Sea is at the depth of 200 fathoms, and in the Celebes Sea at 180 fathoms, and in the Pacific at 230 fathoms, it may be inferred that the Sulu Sea is prevented from freely interchanging its waters with those seas by ridges which do not exceed those depths.

In the Sulu Sea easterly winds with fine weather prevail in October, and the northeast monsoon is not established until November.  In January and February it blows hardest, but not with the force of the China seas, and it is felt strongest before the openings between Panay and Negros, and Negros and Mindanao.  At the end of May southwest winds begin to blow, and in a month become established, to terminate in October, bringing with them a season made up of rain squalls and tempests, which take place principally in July and August.  In September a heavy mist hangs about the coast of Mindanao.

The island and province of Paragua is the most western of the Philippine Archipelago, and is situated to the north of Borneo.  It is long and narrow, following a northeast direction, and nearly closes on the southwest the Sea of Mindanao, which enters from the China Sea by Balabac Strait on the south and between Mindoro and Paragua on the north.  A chain of high mountains, some 6,560 feet high, runs lengthwise of the narrow belt formed by the island, whose length is 266 miles.  The northwest and northeast slopes are narrow.  The island has extensive and well protected harbors and bays.  The area is 2,315 square miles and the population 45,000.

The capital is Puerto Princesa, with a population of 1,589.

Panay is divided into three provinces, viz:  Capiz to the north, Iloilo to the southeast, and Antique to the southwest.  In general it is wild, with very high coasts, except in the northeastern part, where the latter are somewhat marshy.  A mountain chain crosses the island from Point Juraojurao on the south as far as Point Potol on the north, following a direction almost parallel to the western coast.  Large groups of sierras branch out to the right and left of the central chain; on the eastern slope begins another chain, running northeast to the extreme northeasterly point of the island.  Owing to its cragginess, it has a great number of streams running in different directions.  The area is 4,540 square miles.