Scientific Theories.

The first scientific theory advanced to explain the cause of eruption in geysers was that of one Mackenzie, who, in 1811 suggested that the expansion of imprisoned steam brought about the characteristic display. Mackenzie's theory inferred the existence of a subterranean reservoir connected with the geyser. It was submitted that steam collected in the dome-like roof of this underground cavern, and that by reason of the pressure exerted by the weight of the water in the well of the geyser, or by the ingress of further water from below, or because of both, this imprisoned steam expanded until it attained sufficient power to escape violently by means of the well and carry the superincumbent mass of water with it. It is a well-known fact that steam held under pressure expands, and this was considered to be the fundamental principle of geyser activity.

Until comparatively recent times little further progress had been made in the scientific investigation of the geyser, and it was not until the French geologist, Robert, discovered that the water in the depths of the Great Geyser of Iceland registered a temperature considerably above the point at which water boils at the surface, that the earlier and simpler hypothesis was abandoned.

This discovery was supplemented by the researches of Descloiseaux, and the scientific work of Bunsen, Tyndall, and others. Bunsen had demonstrated that water under pressure will remain liquid at a temperature very much above that of the ordinary boiling point. When in this page 54 condition water is said to be superheated, and if the pressure be suddenly reduced is virtually a high explosive. This is a significant fact, and it is now generally recognised that the basic cause of geyser action is the presence of superheated water or steam in the geyser well.