Indian Archipelago, Or Malay Archipelago, a vast aggregation of insular groups S. E. of the continent of Asia, lying between the China sea, the Indian ocean, and the Pacific. In the widest sense it includes the Philippine islands and Papua, and extends from about Ion. 95° to 151° 20' E., and from lat. 19° 40' N. to about 11° S., being about 2,100 m. wide and upward of 4,000 m. long, and bisected by the equator. With the exception of Australia, the Indian archipelago contains the largest islands of the world, namely, Borneo and Papua. These, together with Gilolo, Celebes, and Sumatra, form a range extending along the equator, and all except Papua crossed by it; a similar but shorter range, further S., is made up mainly of Java, Sumbawa, Flores, and Timor; and in the north the principal islands are Mindanao and Luzon, of the Philippine group. The seas which separate the islands are variously designated. These are: the Java sea, between Java and Borneo; the Sooloo sea, between Borneo and the Philippines; the Celebes sea, between the Philippines and Celebes; the Flores sea, between Celebes and the Timor group; and the Banda sea, between Celebes and Papua. The depth of water between the Asiatic mainland and Sumatra, Java, and Borneo, respectively, nowhere exceeds 100 fathoms, nor is the sea between Papua and Australia deeper than this; but these shallow seas are divided by a line of deep water in which lie Celebes, the Moluccas, Flores, and the adjacent islands.

Wallace regards the archipelago as naturally comprehending the Malay peninsula, S. of Tenasserim, the Nicobar islands, and the Philippines. Exclusive of the latter, he classifies its islands into five groups, as follows: 1, the Indo-Malay islands, comprising the Malay peninsula and Singapore, Borneo, Java, and Sumatra; 2, the Timor group, comprising the islands of Timor, Flores, Sumbawa, and Lombok, with several smaller ones; 3, Celebes, comprising also the Sula islands and Booton; 4, the Moluccan group, comprising Booro, Ceram, Batchian, Gilolo, and Morty, with the smaller islands of Ternate and Tidore, Makian, Kaioa, Amboyna, Banda, Goram, and Matabello; and 5, the Papuan group, comprising Papua, with the Ar-roo islands, Mysol, Salawaty, Waigioo, and several others. The area in English square miles of some of the principal islands is approximately as follows:

Amboyna.......

300

Bali............

2,200

Banca.........

5,000

Banda........

130

Batchian.........

800

Booro........

2,000

Borneo..........

300,000

Celebes...........

70,000

Ceram.........

6,500

Flores..........

9,000

Gilolo.........

5,800

Java and Madura.....

51,300

Lombok..........

1.850

Sumatra...........

160.000

Sumbawa........

6.000

Timor...........

11,500

It will be seen that neither Papua nor the Philippines are embraced in this table. The latter islands are chiefly under the dominion of Spain, but in the other parts of the archipelago the government of the Netherlands is the predominant power. According to the latest returns, principally of 1871-'2, the colonial possessions of the Dutch in the archipelago have an aggregate area of about 600,000 sq. m. and a total population of 24,300,000. They comprise the whole of the island of Java, extensive territories in Borneo, Sumatra, and the Moluccas, and about 29,000 sq. m. in Papua. - Physically, the most striking and characteristic division of the archipelago is into volcanic and non-volcanic regions. A long line of active and extinct volcanoes, constituting one of the most remarkable volcanic systems in the world, extends from Sumatra eastward through Java, Bali, Lombok, Sumbawa, Flores, and Timor, beyond which it trends northward through Banda, Amboyna, and Gilolo to the northern peninsula of Celebes, and thence to the Philippine islands. The islands traversed by this belt are subject to frequent earthquakes. The non-volcanic regions lie on both sides of it. There are no volcanoes in Papua or Borneo, and in the latter island earthquakes are unknown.

The loftiest mountains in the archipelago are in Java, Borneo, and Sumatra, where numerous peaks rise to a height of 10,000 ft. and some much higher. The climate is one of almost uniform tropical warmth and moisture, giving rise to a dense and luxuriant forest growth, which overspreads all the islands except Timor and those immediately around it; in these there is a deficiency of rain, which is attributed to the proximity of the arid regions of Australia. The line of separation between the two great zoological provinces, known as the Indian and the Australian, divides the archipelago, passing between Celebes and Borneo, and through the narrow strait of Lombok. This is but 15 m. wide, yet, according to Lyell, the contrast between the animals on the two sides of this channel is as great as between those of the old and new worlds. W. of it the fauna is strictly Indian; E. of it a distinctively Australian fauna is met with; and it is conjectured that the two great regions thus distinguished once formed parts of the Asiatic and Australian continents respectively.

The geographical distribution of the two typical races of men inhabiting the archipelago corresponds closely to that of the animals; the Indo-Malays being found in the western islands, while the Papuans dwell further eastward. - Detailed accounts of the principal islands of the Indian archipelago will be found under their respective titles. For their general history, see " The Indian Archipelago, its History and Present State," by Horace St. John (2 vols. 12mo, London, 1853). The natural history of the region is ably treated in "The Malay Archipelago," by Alfred Russell Wallace (London, 1869). See also "Travels in the East Indian Archipelago," by Albert S. Bickmore (8vo, New York, 1869).