Its last explosion occurred in the year 1680.

Since that date it had remained quiet.

But now the tremendous subterranean forces which had originally called it into being were beginning to reassert their existence and their power.

Vulcan was rousing himself again and beginning once more to blow his bellows.

So said some of the sailors who were constantly going close past the island and through Sunda Straits, which may be styled the narrows of the world's highway to the China seas.
Subterranean forces, however, are so constantly at work more or less violently in those regions that people took little notice of these indications in the comparatively small island of Krakatoa, which was between five and six miles long by four broad.
As we have said, it was uninhabited, and lying as it does between Sumatra and Java, about sixteen miles from the former and over twenty miles from the latter, it was occasionally visited by fishermen.