which, in the course of future events, became the prison of one of
Europe’s greatest monarchs.
[Repeated outpourings of lava would in time raise the crater-edge
above the surface of the water, and the flow of lava inclining from
it would eventually bring up the land to the same elevation. At an
early period the crater would doubtless have its edge intact, and would
necessarily contain water, which, during the interval between
volcanic action, would mix with bits of broken rock, débris, and
dust rolling down into it from the disintegration of its sides, and
produce volcanic mud. A renewal of volcanic activity would first
of all discharge from the crater this mud, accompanied with steam
and water ; the rubble, or small fragments of rock, which, being
heaviest, would sink to the bottom, would next he shot forth, and
finally the molten lava would follow, thrown up high into the air
amidst smoke, dust, and heavy clouds, just as in the present day we
witness it at Vesuvius ; sometimes so high that detached fragments
of lava, rendered spherical by their passage through the air, would
descend in the form of bombs weighing half a ton or more. The
lava would, for the most part, however, descend in huge sheets of
liquid matter. A period of quiescence, or rest from volcanic discharge,
extending over a century or two,* would then intervene,
when another similar outpour would follow : first mud, then
rubble, followed by the pure lava, and this would, with intervals
of rest, be repeated through hundreds of centuries until
the edge of the great crater was built up to thousands of feet in
height, with the land on its outer sides, excepting th a t towards
which the prevailing wind blows, sloping outwards at such angles
as the flow of lava naturally takes, probably 5° or 7°. Now this is
precisely what we find on examining that part of St. Helena
which is outside of the crater-walls. The whole of this portion of the
Island is thus built up of numerous layers of mud, rubble, and lava ;
occasionally the former two are missing in the regular order, and
beds of lava overlie beds of lava, but such is the exception ; and
although it is difficult now, in consequence of disintegration and
surface-soil overlying them, to trace the distinct strata, it is easy to
count, on the northern face of the Island, at least forty or fifty
* C. Piazzi Smith states, with reference to Teneriffe, that volcanic outbursts occur once in
a century.