10 ICELANDIC SCENERY.
has witnessed. Although fully alive to the fact that, throughout the globe, a
mere crust inteiwenes between us and the vestiges of similar phenomena, it
is not until our feet press the blistered lava-bed, and we actually see around us
the vast blocks which once fell thundering into the positions they still occupy,
that the mind wakes to a conception of the sublimity and grandeur of such a
scene.
The whole of the south-western peninsula of Iceland presents the appearance
of ha-sing been poured forth as a vast continuous lava-stream. Along the eastern
boundary of this tract may be seen a number of well-defined cones, which constitute
the flank company of a series extending diagonally across to the northeastern
extremity of the island. Those in the neighbourhood of Rekiavik, and
stretching in a south-westerly direction down, towards Rekianess, would seem to
have been thrust up at a period anterior to the passage of the great lava-stream,
inasmuch as they rise up suddenly from the general level, and thus indicate its
gradual elevation around their bases. But at the present day there remains no
direct evidence to show fi'om whence the stream bowed. The distance of its
central portion from the two great southern foci of convulsion, namely Hecla
and Eyefialla, is about sixty miles. I t is nevertheless quite possible that it may
have flowed from one of these, inasmuch as, during the eruption of Skaptar Jokul
in 1783, two streams were given off, one of which extended to a distance of fifty
miles, with a breadth vaiyung Rom twelve to fifteen miles, and an average depth,
where spread out on fiat tracts, of 100 fe e t; whilst the other reached to a distance
of forty miles, with an average breadth of seven miles, and the same depth as
the preriously mentioned stream. But in some of the gorges, between the
mountains through which these streams forced their way, they actually attained
the enormous depth of upwards of 600 feet.
The shore along the fiord near Eekiavik is composed entirely of huge scori-
aceous blocks of lava, the colours of which vary from a slaty blue, to purple, brick-
red, and black. All are more or less spongy in their structure, and, except
where they have been subjected to attrition within the tide-marks, retain the
sharp irregular emery-like surface so characteristic of the lavas and pumice
masses. Even the small boulders and pieces of shingle along the water-line,
which have been subject to long-continued violent attrition against each other,
although rounded in outline, present the same peculiarity; whilst the resultant
OBSIDIAN DUST.
sand consists of minute angular particles which never lose their primary keenness,
under any amount of comminution. The same remark applies to the more
glassy obsidian-like substance of which the soundings on the southern coast consist.
This deposit has been derived, in all probability, from the atmosphere during
the eruptions; and it is somewhat extraordinary that it should be almost entirely
free from particles of true lava or pumice. So far as the soundings have hitherto
gone, this peculiarity is invariably observable. I t would therefore appear that
the clouds of volcanic dust with which the atmosphere is loaded, and which has
been known to extend to the coasts of Norway, the Faroe Islands, and even
Shetland, constitute the true basis of the molten mass of the volcano, the lavas
and pumice being the overflowing scum that collects upon its upper surface.
As far as I have been able to learn from persons who have travelled in the
neighbourhood of the obsidian veins, these do not occur at great elevations on
the sides of the volcanic cones, but appear suddenly and end as suddenly.
Should this really prove to be the case, it would indicate that the streams of
obsidian were poured out through lateral channels, .situated below the level at
which the fused mass within the body of the volcano assumes its frothy character.
Pent up as is the gaseous matter within the cellular cavities, under an inconceivably
vast pressure, it is easy to perceive that such portions as are thro^vn up
from the mouths of the crater itself would be shivered into innumerable minute
atoms on escaping into the atmosphere, and, in this state, be borne far and wide
with its currents.
Out of 25 soundings made up to this date, bottom has been brought up, in
greater or smaller quantity, seventeen times. Of this number 10 soundings have
been effected with the greased sinker, and 5 with the conical cup.
I have devised, and submitted to Sh Leopold M‘Clintock, a modification of the
“ Clams” which he described to me as having been employed by Sir John Ross
many years ago. Instead of clams I have suggested cups, closing on hinged
levers, and available with the hollow Brooke’s sinkers supplied for use on board
the ‘Bulldog.’
July 13.— Called on the leading residents at Rekiavik, and experienced from
them the cordial hospitality for which they have always been remarkable. The
name of the ship seemed to afford the little community a standing joko as being
peculiarly applicable to “ John Boole.” I t is only to be hoped that theh ideas
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