In New Guinea the British territory was in 1914 approximately 87,786 square miles, while the German possessions in the north of the principal island, and including the Bismarck Archipelago, amounted to roughly 180,000 square miles. German New Guinea was, upon the hoisting of the German flag, renamed Kaiser Wilhelm's Land, New Britain became Neu Pommern, and New Ireland took the name of Neu Mecklenburg. Neu Pommern and Neu Mecklenburg are the principal islands of the Bismarck Archipelago, the area of which is estimated at 48,000 square miles. Lying in the equatorial region, the climate of New Guinea and the Bismarck Archipelago is hot and humid, and the seasons may be roughly divided into the comparatively dry period of the southeast monsoon from about May to November, and the rainy west or north-west monsoon. The annual rainfall is heavy, being some 150 inches on the sea-board, and far more on the highlands which intercept the moisture-laden clouds. Like the majority of the islands of the South Seas, New Guinea coastal districts are infested with mosquitoes, and malarial fever, which affects Europeans as well as natives, is prevalent. It occurs in more or less severe forms, and occasionally terminates fatally. The eradication of the mosquito pest by petroleum spraying, which has proved such a marked success in the Panama regions, is now being attempted in all malarial-stricken countries, and will, when accomplished, no doubt bring immunity from malaria to New Guinea. The coastline on the mainland of New Guinea is fringed by coral reefs and a line of large and small islands, and is indented by fine bays; but to reach them the navigation is extremely difficult. In the narrow passages between the islands and between the reefs the current is so strong and runs so continuously for days at a time that a sailing boat can do nothing but lie at anchor waiting for a turn in the tide, and some have had to wait for a fortnight before they could get through. The chief danger to navigation is the number of coral reefs that are scattered about the coast, very few of them charted. Sometimes there is enough water to make it safe to pass over them, and then the coral presents a beautiful sight--snow-white with long branches, or bright-red: then the sudden drop into deep, dark nothingness, at the edge of the reef that rises sheer from bottomless depths. The islands are volcanic and the Kaiser Wilhelm territory in particular is very mountainous, the most prominent feature of its configuration, especially on the east coast, being the magnificent mountain ranges which in places rise steeply from the narrow fringe of the low coastal lands. Snow-capped mountains and volcanoes, rising to a height of 15,000 feet or more, are reported to have been seen in the interior, which is still considerably unexplored. There are a large number of mountain streams on all the large islands, but so far no navigable river has been found in the Archipelago.