ottom of an immense basin, measuring fully
a mile in diameter, the sides of which were formed of lofty precipitous
cliffs of volcanic rock, so smooth and so nearly vertical that nowhere,
at least in their immediate neighbourhood, could they discover a spot
capable of being scaled. Before them, and occupying the whole bottom of
this enormous basin, stretched a placid lake, the water of which was as
clear as crystal. A thin filmy veil of vapour rose everywhere from the
surface of the water, softening the hard outlines of the more distant
landscape, and imparting an aspect of dreamlike witchery and unreality
which it would certainly have otherwise lacked.

"Why, the water is tepid!" exclaimed Sir Reginald, plunging his hand
into the lake and raising a small quantity of its water in his palm, to
ascertain by taste whether it was fresh or salt.

The colonel thereupon thrust _his_ hand down, and satisfied himself by
experiment of the truth of his companion's statement. It was even more
than tepid, it was positively _warm_.

The two were still discussing the probable reason for this phenomenon
when their attention was suddenly arrested by a curious movement of the
water in the centre of the lake. First a few tremulous ripples
appeared, spreading outward from the centre; then the disturbance became
more pronounced, until, within a minute, an area of some thirty or forty
yards in diameter had assumed an appearance of violent ebullition.
Suddenly a jet of steam and spray shot up out of the centre of this
disturbed spot; and then, before either of the two bewildered spectators
could find time to remark upon so curious a phenomenon, an immense
column of purest crystal water shot into the air to a height of at least
two hundred feet, and, gleaming and flashing in the sunbeams as it
soared away above the level of the encircling cliffs, spread out into a
dome-like sheet, and, leaving behind it aloft a dense cloud of vapour of
dazzling whiteness, fell again into the lake in the form of a shower of
boiling water.

"A geyser!" exclaimed the baronet. "A geyser! and of such grandeur that
the Great Geyser of Iceland, which I have seen, sinks into the utmost
insignificance compared with it."

"You are right," acquiesced Lethbridge. "I too have seen the so-called
Great Geyser, and admired it immensely; but after this--"

He finished with a shrug of the shoulders so expressive that there was
not the slightest need for words to expl