202 



I C E L 



Iceland, the blue holes above mentioned were once eruptive also, 

 ^,— v^^— ' and were styled by an English traveller tlie Roaring Geyser, 

 and that it was only on that geyser becoming tranquillized 

 that the present Great Strokr began its outrageous prac- 

 tices. 



The water of the Geysers is perfectly pure in appearance, 

 and notwithstanding the sulphureous smell, may be used in 

 cooking, or even to drink. In reality the infusion of foreign 

 matter is extremely small, being little more than a thousandth 

 part of the «hole, as appears from the following statement 

 of Dr Black regarding a quantity of 10,000 grains (about 

 one-sixth of a gallon) : — 



Soda 0-95 



Alumina 0*48 



Silica 540 



Muriate of soda 2'46 



Dry sulphate of soda. .. 1'46 

 Total 10-75 



Small as is this proportion of silica, it has been enough 

 in time to form the thick incrustations around the geysers, 

 and even the mount on which the Great Geyser is situated. 

 These incrustations are usually of a dull colour and great 

 hardness, their surfaces being efflorescent, like the top of 

 a cauliflower, wherever the water falls in a plasli, in other 

 places smooth. 



Our space allows us only to glance at the geysers con- 

 taining an infusion of fine clay. These have caused, in 

 the superior part of the slope, several deposits of various 

 colours, resembling the finest pigments. 



The formation of this mud, and other products of the 

 hot springs of Iceland, out of the materials presented by 

 the rocks of the country, offers the most curious subjects 

 of inquiry for the chemist. Of these products there is one 

 of some commercial importance, and which calls for special 

 attention, viz., sulphur. It is produced in large quantities 

 at two places — Husivik, on the N. of the island, and Kru- 

 sivik, within a day's ride of Reikiavik. In the latter in- 

 stance, in a hollow at the bottom of a tuff hill, we find 

 thick deposits of red and blue clays, mixed with iron pyrites, 

 and of which the temperat\ire, a few feet down, is nearly 

 equal to that of ordinary boiling water. The hot springs 

 gushing through these deposits form the sulphur in crystals 

 and in layers, requiring very little refining to prepare it for 

 use. 



The mud volcano of Reykialid, near Myvatn, occupies 

 the crater of Mount Krabla, one of the principal volcanoes 

 ol Iceland, and is thus described by Henderson, who made 

 the circuit of the island during the year 1S15. "At the 

 bottom of a deep gully lay a circular pool of black liquid 

 matter, at least tliree hundred feet in circimiference, from 

 the middle of which a vast column of the same black liquid 

 was erupted with a loud thundering noise. This column 

 is equal in diameter to that ejected by the Great Geyser at 

 its strongest eruptions. The height of the jets varies 

 greatly, rising on the first propidsions of the liquid to about 

 twelve feet, and continuing to ascend, as it were, by leaps, 

 till they gain the highest elevation, which is upwards of 

 thirty feet, when they again abate much more rapidly than 

 they rise ; and after the spouting ceases, the situation of the 

 aperture is rendered visible only by a gentle ebullition, 

 which distinguishes it from the general surface of the pool ; 

 the eruptions take place every five minutes, and last about 

 two minutes and a half." In the same vicinity are the hot 

 springs of Husavik, which, though they bear no comparison in 

 magnificence to those of Skalholt, are extremely interesting 

 in many respects. The pipe of one of them, the Oxahver, 

 which is said to have derived its name from the circum- 

 stance of an ox having fallen into it, is about eight feet in 

 diameter, is surrounded with a strongly incrusted brim, and 

 shortly below the surface trends to one side, and becomes 

 quite irregular. Its jets rarely exceed twenty feet in height, 

 but, according to Henderson's account, they are conducted 

 with the utmost regularity in point of time. It was amongst 



K 

 A N D. 



the beautiful incrustations formed around the basin of this Iceland, 

 spring that Mr Rose of Edinburgh, during his mineralogical *- j -i^ -' 

 excursion a few years ago, observed that variety of apo- 

 phyllite, to which the synonyme of Oxahverite was subse- 

 quently applied. 



Though it cannot be denied that these springs have some 

 commmiication with the volcanoes which abound in the 

 island, yet it is a remarkable fact that they are seldom found 

 very near them, although dispersed throughout the whole 

 country. When their situation suits, they are turned to 

 good account by the inhabitants, both as bathing quarters, 

 and for various culinary purposes, in boiling fish, evaporat- 

 ing sea-water, and the like. At Reikhali there is a cele- 

 brated bath of this description, which was constructed six 

 hundred years ago by the famous Snorro Sturleson. It is 

 fourteen feet in diameter and six feet deep, being supplied, 

 by means of covered conduits, both with hot and cold water, 

 from springs about a hundred yards distant, so that any de- 

 sired temperature might be obtained. 



Iceland is one mass of igneous rocks, of two classes — first, 

 traps and tuffs arranged in beds generally little inclined, and 

 presenting in some places sectional cliffs of from three to 

 four thousand feet in height ; second, trachytes in huge 

 irregular masses, constituting the principal mountains of the 

 interior. Different as they are in general appearance, a con- 

 )>cction can be established between them by the clearest 

 intermediate steps, exhibiting a progress in time from the 

 formation of the traps under a superincumbent ocean, to the 

 tremendous subaerial volcanic operations which produce 

 the trachytes, and which cannot yet be said to be at an end. 

 The traps are intersected by numerous veins, and curious 

 appearances are presented where these have alone survived 

 the disintegrating forces. The surfaces of some of the lavas 

 which Sir George Mackenzie observed in Iceland he de- 

 scribes as not unlike coils of ropes or crumpled cloth ; in 

 other respects they appear to resemble the lavas of recent 

 volcanoes elsewhere, being, like those of jEtna, thrown up 

 into large flattened masses. These, it is well known, are 

 produced by the formation of a crust on the lava during its 

 course, which, as it accumulates, breaks through the hard- 

 ened surface ; and thus, when it cools, leaves a wide ex- 

 tended plain of the most rugged and impassable description. 

 In some places the surface has swelled during the course of 

 the lava into knobs, from a few feet in diameter to forty or 

 fifty, many of which have burst, and disclose caverns lined 

 with melted matter in the form of stalactites. Of these some 

 remarkable instances are mentioned amongst the extremely 

 rugged lava of Buderstad, in the vicinity of the Snaefell 

 Yokul, where several of the caverns extend to the depth of 

 forty yards. Stappen, in the same part of the island, pre- 

 sents, for the extent of about two miles, the most striking 

 columnar appearances, both in the cliffs which form the 

 shore, and in the numerous insulated rocks which appear at 

 different distances from the land. Amygdaloid forms the 

 larger portion of the eastern extremity of the island, and it 

 is imbedded in this that those splendid specimens of calca- 

 reous spar par excelle?ice denominated Iceland-spar are 

 found. This rock is likewise the matrix of all the different 

 varieties of the zeolite tribe, of the magnificent calcedonies, 

 and in fact of most of tlie fine minerals which have long 

 rendered Iceland so celebrated among collectors. Fossilized 

 wood is found in several places ; that variety termed Sur- 

 turbrand is peculiar to the north-eastern volcanic district. 

 It is remarkable that the specimens hitherto brought liome 

 of this last substance appear to be oak. It burns with flame, 

 and can be cut and shaped like jet ; but from its brittleness 

 does not admit of being sliced into shavings. Pumice, ob- 

 sidian, and other volcanic minerals appear in great beauty 

 in many districts of the island, particularly near Hecla, and 

 to the north of Krabla. 



There is little remarkable in tlie zoology of Iceland. 



