The “Warm Lake.”

Roto-mahana, the “Warm Lake” of the Maoris, is the most singular example of a volcanic lake in the islands, for it has been subject to extraordinary changes during a marvellously brief period, the last quarter of a century. Prior to the Tarawera eruption in 1886, Roto-mahana was but a small shallow reedy lagoon of about a mile in length. When Tarawera burst out a huge rift split the mountain from end to end and extended down into the lake at its foot. The waters of the lake, so suddenly gaining access to the hidden fires below, were converted into steam, and then up went the lake bottom and the islands and the terraces on its margin, hurled into the air in one cyclopean convulsion, to be rained down in devastating showers of mud and rock upon the doomed lands around. After the eruption, the emptied lake-bottom was a furnace of fiery volcanoes and craters of boiling water and boiling mud; then, gradually cooling, the fresh lake was formed, and now the new Roto-mahana is six miles long, several hundreds of feet deep, and engulfs an area approximately thirty times that of the lake of 1886. Along the northern and western shore line there is a zone of tremendous hydro-thermal activity. Here one may boat for two miles along geyser-pitted cliffs, strangely painted by chemical action. The cliffs are steaming from lakeside to skyline, and thousands of warm vapour-wreaths curl like white smoke into the upper air. Nor is the heat confined to the cliffs. The water on which you are floating is boiling in many places, and here and there you feel below your boat the thump of water-hidden geysers. All around, on shore, and in the lake, are boiling springs. It is Nature's most terrifying laboratory. But even here in this seven-times heated place there is luxuriant vegetable life. Beautiful ferns and mosses grow everywhere, even in the hot spray of the springs, and a soft garment of green shrubs climbs to the summit of the steam-soaked heights.