m
of our refinement were not based on the grinning demon that passes muster as a
figure-head, and vouches for our “ fancy ” habits by having its neck encii'cled with
a huge saw-toothed collar.
Dr. Hjalthelin, the chief surgeon of the settlement, whose acquaintance I had
the pleasure of making today, informs me that Kotla (the volcano which burst
into action in the middle of May) is one of the largest in the island. For some
weeks prior to the eruption, the wells and spiings dried up and several shocks
of earthquake were experienced. Towards the end of May, it cast forth vast
masses of lava and ice, mixed. This is precisely what Sir Charles Lyell states
might be expected to take place in the case of the Icelandic volcanos, the cones
of which are more or less constantly covered with perpetual snow*,—his conclusion
being based on the discovery on Mount Etna, in 1828, by Signor Gemmel-
laro, of an extensive glacier over which had flowed the lava-current. “ We may
suppose,” writes Sir Charles, “ that, at the commencement of the eruption, a deep
mass of drift-snow had been covered by volcanic sand showered down upon it
before the descent of the lava. A dense stratum of this fine dust mixed with
scoriae is well known to be an extremely bad conductor of heat.................Suppose
the mass of snow to have been preserved from liquefaction until the lower part
of the lava had consolidated, we may then readily conceive that a glacier thus
protected would endure as long as the snows of Mont Blanc, unless melted by
volcanic heat from below.”
In the recent eruption of Kotla these several conditions would seem to have
been fully answered. I t is well known that the summit of the cone of this
mountain was completely encircled with glacier. During the earlier period of
the eruption the ejected matter consisted principally of small scorite, with immense
volumes of dust, by which the atmosphere was darkened. I t is therefore highly
probable that a considerable layer had time to collect, and thus to protect from
immediate disruption the great mass of ice occupying the depression of the crater.
On the eruption attaining its height, this mass would be rent asunder, in the
first instance, into innumerable blocks of still gigantic proportions; and finally
these blocks, melting and being dislodged by the intensity of the temperatiu'e,
would flow towards the vents and there mingle and be ejected with the general
mass of volcanic matter.
* Lyell’s ‘ Principles of Geology,’ 1853, p. 413.
During the continuance of the eruption, great sickness and mortality are said
to have occurred amongst the inhabitants of the islands and their cattle. Forty
thousand sheep perished in the short space of sis weeks. Similar results are
recorded as having attended previous outbursts. They are referred to, not as
secondary results of the phenomena, but as being directly and entirely due to the
dissemination of mephitic vapours. Now although the gaseous products of volcanic
action are no doubt highly deleterious, I cannot help thinking that an undue
amount of direct influence is supposed to attach to them. Leaving out of the
question the effect on the animal economy of inhaling minutely pulverized particles
of mineral matter of any kind—effects which can be demonstrated too
frequently amongst our own manufacturing towns, without having to seek for
illustrations in volcanic regions—I think it highly probable that fear and mental
depression must be regarded as the mephitic influences most potent in the production
of the evils. No more conclusive proof is needed of the wonderful extent
to which fear may operate, than the almost universal sensations of “ sickness ”
and “ giddiness ” said to attend an earthquake. As the shocks rarely last above
a minute or two, it is obviously absurd to refer these sensations to any more
palpable cause than alarm ; and we may readily understand, therefore, how such
sensations, if protracted for considerable periods, and aggravated by the intensity
of the predisposing cause, may bring about the most alarming or fatal consequences.