exposed to ashes, sand, &c. from the adjacent volcanoes, it is much blacker than any of the Yökuls along the coast, and its aspect is rendered still darker by the rocks which appear in it at different places, and which it has carried along with it from their original beds in the interior. But what makes it peculiarly remarkable, is the alternate progression and retrogradation to which at certain periods it is subjected. Some years it pushes forward till nearly in a line with the ancient promontory of Lomagnupr, and then moves back again to the distance of more than half a mile. In 1727, when both the Öræfa and Northern Skeiderâ volcanic Yökuls were in activity, this low Yökul began to rock, to the great danger and consternation of some people who happened to be travelling on the sand before it. According to the account they afterwards gave, it moved backwards and forwards, undulating at the same time like the waves of the sea, and spouting from its foundations innumerable rivers, which appeared and vanished again almost instantaneously, in proportion to the agitation of the Yökul. As the progress it made was inconsiderable, the spectators saved themselves on a sand-bank, but the suddenness and unexpectedness with which the rivers continued to rush forth, rendered it impossible to travel any more that the whole summer. way On reaching the middle of the sand, we fell in with the remains of the projection that took place in 1787, consisting of an elevation of from thirty to fifty feet, and covering an extent of several acres, the surface of which has the same appearance with the rest of the sand. At first I had no idea of its being any thing else than an immense sand bank, or a rising ground, which had withstood the violence of the floods; but, after riding more than a mile on it, I discovered that I was proceeding over masses and caverns of ancient ice; and had it not been for the intelligence and experience of our guide, I certainly would not have hazarded the prosecution of my journey in this direction. Descending into a hollow, we passed through between extensive pools of white water,

* See Olafsen's og Povelsen's Reise, p. 780.

*

and rounded several sources from which considerable rivers were poured forth into the sand. This region may be about three quarters of a mile from the present margin of the Yökul; and near the middle of the intervening space are a number of inferior heights which have been left on the regress of the Yökul in 1812, the last time it was observed to be in motion.

To explain the cause of these phenomena, recourse has been had to a subterranean communication between this Yökul and the neighbouring volcanoes; but its progress may be accounted for on the same principle with that we have adopted in regard to Breidamark Yökul; and it seems equally natural to conclude, that its falling back is occasioned by the sliding down of the hinder parts of the Yökul into the low space that had been occupied by the vast collection of water previous to its having rushed into the icy caverns in the interior of the mountain, from which it has again been emptied into the plain. This supposition is confirmed by the circumstance of the retrogression happening immediately after the mountain ceases to protrude, and it has discharged itself of the immense surplus of water with which it was glutted; and is rendered still more probable by the consideration, that the foundations of the Yökul must be entirely disengaged by its progress, so that no obstacle can be presented from that quarter to impede its return to its former situation. The undulatory motions observable during its lesser convulsions, seem to arise from the violence with which the water forces its way through the internal caverns, just as its breaking out and disappearing again, almost the same moment, must be occasioned by the falling in of the caverns in the vicinity of the margin. That it was convulsed during the eruption of the adjacent volcano was a necessary consequence of the deluge of hot water that mountain poured forth, as there was no other way for it to make its escape than the low ground occupied by the moveable Yökul; but that its movements are dependent on volcanic eruptions, is contradicted by the fact that it has both advanced and retired during the period the volcanoes have been in a state of

inactivity. Whether the sparks of fire said to have been seen above it* did not originate in the volcano behind, may justly be doubted, as it is certain the account of the playing of flames in the middle of the fresh water lake Grimsvötn, during the eruptions of the Northern Skeiderû Yökul, † is wholly fabulous; or the sparks may have been produced by the violent collision of certain mineral bodies confined within the masses of the Yökul when these were torn and convulsed by the fury of the water below. The phenomena of these vacillating Yökuls would receive much elucidation, from a survey of the situation and appearance of those parts of them which lie towards the interior of the island; but the dangers connected with every attempt to explore them, are more than sufficient to damp the zeal, and check the enterprise, of the most impassioned lovers of natural history. ‡

At the western extremity of the sand we came to several rivers, that are known by the general name of Gnupsvötn, some of which we found still more formidable than the Skeiderâ. These rivers are defended on the right by the long narrow mountain Lomagnupr, which projects into the sand, and bears every mark of its having been a promontory in former times. It is at least 1500 feet high, and is composed of rough brown tuffa, in the matrix of which is imbedded an infinite number of small pointed stones of a bluish colour, which I take to be pieces of basalt. Of this stone I saw some fine pentagonal specimens at the base of the mountain, but, owing to the gloom which the shadows of evening had

See Olafsen's og Povelsen's Reise, p. 780.

+ Ibid.

Before leaving the subject of the moveable ice-fields in Iceland, I cannot but lay before the reader the following short account of a similar field in the valley of Iustedal in Norway: "The situation and appearance of this field of ice are very variable. Sometimes it continues to protrude into the vallies near it for the period of from thirty to sixty years, and again recedes for a time. When it moves forward, it cracks to the depth of several thousand feet; and when it returns back to its original position, the rents are all closed up, as if the mass had never been split. In its progress it has such a force, that it pushes before it stones or rocks, as large as houses; and should they happen to get jammed in between the ice and an adjoining mountain, they are crushed to pieces as it pas

ses.

On receding, it leaves behind it a sterile, dry, and sandy soil, on which no grass will ever afterwards grow." BOMARE'S Nat. Hist. Kib. 1769, vol. iv. p. 60, 61.

already cast on its sides, it was impossible to discover their original bed.

We here proceeded with considerable difficulty, being directly above the river; and the track lying across large heaps of small stones that had been washed down by the torrents, had no solid foundation, but threatened, at every step, to give way, and plunge us into the raging flood, from which there was not the least possibility of extrication. Turning round the extremity of the mountain, which hangs almost directly over head, and resembles a vast square tower, at the angle of two ranges of ancient buildings, we fell in with numerous heaps of stones, and immensely huge masses of tuffa, which have been severed from the mountain, and hurled down into the plain, during the rockings occasioned by an earthquake in 1789. We now crossed a tract of lava, called from its colour "the Brown Lava," which, as no mention is made of the circumstance in the ancient annals, is supposed to have flowed previous to the occupation of the island; and passing the farms of Gnúpstadr and Raudaberg, we forded the Diupâ, a river of considerable breadth, the bottom of which is full of large stones, so that its passage attended both with difficulty and danger; and arrived, about ten o'clock at night, at the parsonage of Kálfafell, where I was kindly received by the clergyman, Sira Jon Jonson, and pitched my tent a little to the south of the church.

The parish of Fliotshverfi, of which Sira Jon is minister, contains only a population of about seventy souls; the tract having been much injured by the volcanic eruptions described in the following Chapter; yet, among that number of people, there only existed one Bible, besides the copy belonging to the church. They had long uttered complaints of the want of the sacred oracles; but as there was no appearance of any supply, they had ultimately given up all hopes of ever seeing them more. Sira Jon is between fifty and sixty years of age, and appears to have more life and activity in religious concerns than many of his brethren. The exertions of the Bible Societies commanded his admiration, and excited the liveliest emotions of gratitude and praise.

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CHAP. VII.

West Skaftafell's Syssel-Skaftár Volcano-Eruption of 1783 described-Sida-Hörgland Hospital-Icelandic Leprosy Kyrkiubæ—Basalts-Landbrot-Passage of the Kudafliot-Thyckvabæ-Myrdals-sand-Wild Corn -Kötlugiár Volcano-Its Eruptions described-VikHafursa-Narrow escape.

THE

HE two subdivisions of Skaftafell's Syssel are separated from each other by the Gnupsvötn, and the traveller, on passing that boundary, leaves the regions of perpetual ice and snow, and enters a tract, which, though greatly defaced by the terrible convulsions of nature to which the last century was witness in this neighbourhood, still exhibits ample specimens of that beauty and fertility for which it has been renowned. The Northern Skeiderâ and Skaptâr Yökuls lie at a considerable distance back from the farms; and the low flat hills which occupy the intermediate space, while they screen the inhabitants from the cold northern blasts of winter, afford their flocks and herds a pretty luxuriant pasturage. The numerous cottages that line the base of the hills, the rich vegetation which clothes nearly two-thirds of the declivity; and the beautiful basaltic pillars appearing among the cliffs above, the tops of which are met by the descending heath: all combine to render the districts of Sida and Fliotshverfi the most delightful of any in Iceland. The latter district, however, which is the most easterly, has been exposed to two sad disasters since the middle of last century. In 1753, an eruption of the Northern Skeiderâ Yökul took place, which, overcharging the Diupâ, (Deep River,) it not only overflowed its banks, but gave rise to a new tor