Chapter VIII: Section I: To Krísuvík, the Western Sulphur-Field

Mr Chapman and I determined to secure comparative novelty by a “hysteron proteron,” beginning with the “Cope” and ending with the Gusher and the Thingplain Lake.

We hastily collected the small quantity of _harnoys de gueule_ absolutely required--man eats less when travelling, and more when voyaging. Our stores represented a ham, one serving for one mouth per month; a couple of sausages, to be avoided when thirst is threatened; four loaves of rye-bread (each 6 lbs. = one man per week); snuff, cigars, and pigtail for friendship; small change for £5; and, lastly, two mighty kegs of schnapps, the load of one-twelfth our carriage. The Fylgjumaðr (leader) was Paudl (Páll) Eyúlfsson, before mentioned as the “French guide;” our Lestamaðr (“last” driver) was “Smalls,” _alias_ Sigrbjörn Björnsson, fourteen years old, and four feet nothing: we are careful to see that they do not monopolise the very best of the eight riding-horses. We ourselves at once become Martednn (Marteinn) Kaupmansson and Ríkarður Burtonsson; and thus having borrowed as much local colouring as possible, we leave, nothing loath, the hard-soft bosom of semi-civilisation.

Spurring hotly over ground now familiar (July 8, 1872), we delayed a few minutes at Foss-vogr to inspect the “sedimentary and sandstone stratifications,” found so interesting by older travellers in a purely volcanic island. They suggested, in early times, to daring spirits that granite might not be Plutonic, and they made the devil-may-care doubt even the eruptive origin of basalt. The travels of Von Waltershausen have settled Foss-vogr and its Palagonite.

There was nothing to keep us at Hafnafjörð, after a longing glance at the “Jón Sigurðsson,” which lay in harbour. A man happened to mention that the one herd of reindeer still haunting this part of the island had been lately seen; it was not our fate to sight them.

At four P.M. we inspected the Kaldá--an exceptional feature. Rising from a little tarn in the northern flank of the lone hill Helgafell, it winds westward down a shapely river-valley. Half of the stream suddenly disappears in a hollow of the right bank, a little below the farm crossed by the high road or path, and the remainder follows suit about two miles farther down. The feature suggested a limitation of the accepted dictum, “Calcareous rocks are almost the only ones in which great caverns and long winding passages are found.” This is true of water-made passages, where carbonic acid has dissolved the limestone; the cooling of the upper lava crust has the same effect in Plutonic formations. The course of the Kaldá is very badly traced in the great map; nor does the latter show where the lower stream reappears.

The next feature of importance was the Lángahlíð, a stepped and buttressed block of trap like Esja, the Akrafjall, and the Skarðsheiði. A tolerably regular triangle to the south-west, it acts bastion to the great lava-plateau which extends from the Thingvallavatn, and our morrow’s ride will subtend its southern flank. Immediately below the western slopes, which are regular, lies the Kleifavatn (cliff-water),[88] a lake of intensely gloomy shore. The dark waters, ending south in a swamp, were lashed by the wind into mimic waves, and the shores were grisly masses, standing and fallen, of dark Palagonite, a conglomerate of small and large breccia, easily washed into gaps and clefts, arches and caverns. I could not but remember the Lake of Hums so similar, and yet so different, under the glowing Syrian sky; the picturesque contrasts of cultivation and desert contrasting with the lava-bound water, and the memory-haunted stream which once found a mouth at Rome--

“In Tiberim defluxit Orontes.”

Cutting across a hill-brow we sighted a tall, white plume whose fibrils, causing many a cough, suggested the end of this day’s march. The Icelandic traveller who has not read “The Great Sulphur Cure” of Dr Robert Pairman, often lands with the idea that inhaling sulphur-vapour is unwholesome, as the sulphuric acid and the sulphuretted hydrogen are decidedly unpleasant: he soon corrects the impression, finding the people of the two great brimstone centres exceptionally healthy. The Krísuvík diggings are upon a line of volcanic hills, running from north-north-east to south-south-west, and their irregular and tormented flanks contrast sharply with the monotonous Lángahlíð wall, rising opposite them. The “Ketill” (caldron) of Krísuvík, a huge “corrie,” whence the puffs come, lies high up: the four “Brennisteins Námur” are low upon the eastern flank, with the little blue pond, Grænavatn, farther to the south. The scene is that of solfataras generally, a distempered land of disordered cuticle, bright red, brass-yellow, slate-grey, pink, purple, pale green, brown-black, and leprous white; the water is milky and slimy, and even the dwarf willow and juniper cease to grow. “Exhalations of sulphurous acid, sulphuretted hydrogen, steam, and sulphur, burst in wild disorder from the hot ground.”[89] Martednn looked at Ríkarður, and _vice versâ_; both had expected not a single block, a mere patch, but a sulphur region to be measured by many square miles.

We passed two huts, one of iron, the other of wood, with ore-heaps lying around them, and, scrambling through a bog, we rode up to the Krísuvík chapel and the three-gabled farm-house of a little widow, Mrs Ingveldr Hannesdóttir. The district is tolerably populous; on the flanks of the various rises we counted five farms, fringed with haystacks, under sticks and turf, and white ponies dotted the long, swampy expanse, between the Krísuvíkfell, a lump north of the chapel, the Arnarfjall to the south-east, capped by a spitz or bec, and the long slope leading to the Krísuvíkurberg, the precipice some 200 feet tall which boldly faces the Deucaledonian main. Unhappily Henderson’s fine port is utterly absent; on the other hand, it is said that an easy line of tramway has been traced from the head of the Kleifavatn to Hafnafjörð.

The day’s work surprised us, we had not yet realised the shortness of the distances travelled over. This mild march also has been called a “maniac ride”--“one of the wildest in the world.” It is, however, only fair to own that we took the lake road, which is not laid down in the map, and that a few yards on either side of the way would offer as many difficulties as the horseman, however ambitious, could desire.

The steepleless chapel, which was not worse than that of Blúdán, had lost its key, and when the latter was found, the cabin proved a store and a lumber-room: clothes hung to the seats, milk stood to cream, and salt barrels cumbered the floor. A coffin, unfurnished, also stood on a beam: the idea underlying this premature precaution is that it prolongs the owner’s life. Here the chapel is the “mountain-stove” of Norway, the Indian traveller’s bungalow, and the Sind mosque in which Kafirs ate pork and drank wine. We pitched the tent near the byres, where broken bottles showed the habits of civilisation, and slept despite the normal evil, cold feet caused by riding in a hard head-wind. The frequent weary halts to adjust pack-saddles should be utilised for restoring circulation. “_Les picotements sont plus incommodes que le froid lui-même_,” justly remarks M. Gaimard’s expedition; and the French doctor advises the feet to be gradually warmed, or they will swell and cause _demangeaisons_, which prevent rest. Above all things avoid the Brazilian wrinkle, so valuable against damp in tropical climates--a glassful of spirits poured into the riding-boots. We must not leave the sulphur-field without some notice of the supply.

From Captain, now Commodore, Commerell’s Reports, dated Leith, July 9, 1857, we learn that “the mines of Krisuvik were worked from 1723 to 1730, with considerable profit; during that year, all the sulphur consumed in Denmark and Norway and the Duchies was obtained from there, but one of the owners, who had also been the director in Iceland, dying, the mines were abandoned in consequence.

“In 1833, a merchant of Copenhagen, a Mr Kenidzen, obtained one large cargo of sulphur from Krisuvik; the affair was managed through an agent or factor, whose mismanagement was the principal cause of failure, since then only a few tons having been taken by the peasants for home use.

“The actual extent of the sulphur beds it is quite impossible to calculate; but from Krisuvik to Hengill (the mountain mass south-west of the Thingvallavatn) forty-seven have been discovered, the distance of the latter (former?) place to Havnefiord (Hafnafjörð) is from fourteen to fifteen miles, but the road is much more hilly. The deposit of sulphur I personally saw at Krisuvik must amount to many thousand tons; hitherto the sulphur taken away has been reproduced in two or three years, all the mines, or nearly all, being in a living state. Sulphur in a pure state, I have little doubt, could be supplied at Havnefiord for £1 per ton.”

We are also told that “Dr Hjaltalín, an Icelander and mineralogist, who was ordered by the Danish Government to report on the sulphur beds, informed Captain Commerell that those at Krisuvik could be worked very easily, producing a large amount of sulphur, and as a speculation would pay very well indeed.”

I need not here enter into the history of the Krísuvík diggings since the date of Commander Commerell’s report, or during Mr Bushby’s concession. Suffice it to say that the concession has now been granted to Englishmen, and that Messrs Randall and Thorne, Curtis and Seymour, are the actual owners. Until 1873, I believe, nothing has been done in the working line--we shall hope to see more activity soon.

After expressing my surprise, as bound to do, at the smallness of the Krísuvík area, it is only fair to own that Commander Commerell’s third paragraph, if correct, is most hopeful. The supply which is puffed away in air can be controlled by walls and roofs, upon which the vapour would be deposited, and thus the period of renewal would probably be reduced from two or three years to the same number of months. As regards Dr W. Lauder Lindsay’s assertion that whilst crude Sicilian sulphur contains 80 to 90 per cent, of pure ore, and that of Krísuvík from 96·39 to 98·20, I am unable to pronounce judgment; but my suspicion is that severely picked specimens were used as averages.

Since my return from Iceland, Mr Charles W. Vincent, F.C.E., published in the _Journal of the Society of Arts_ (January 17, 1873), a valuable paper “On the Sulphur Deposits of Krisuvik, Iceland.” It is here reprinted with his express permission: the importance of the subject will excuse its length, and the reader will exercise his undoubted right of “skipping.”

“The canton of Krisuvik, in the south-west corner of Iceland, has long attracted great interest, on account of its boiling mud caldrons, hot springs, and above all, its ‘living’ sulphur mines; these are all arranged in lines, evidently corresponding to the great volcanic diagonal line stretching from Cape Reykjanes to the Lake of Myvatn.[90] At the present time the greatest amount of volcanic activity is manifested at the southern end of this line.

“In the last century it was the northern end of the volcanic diagonal, near about Myvatn, where, according to the Icelandic records, the kind of pseudo-volcanic action was most vigorous, by which the boiling springs are set in operation and the sulphur deposits are formed; but a violent eruption of the mud volcano Krabla, to a great extent buried the then active strata beneath enormous masses of volcanic mud and ashes, so that the energy has been probably transferred along the line southwards.[91]

“The Krisuvik springs are in a valley beneath some high mountains. They are reached by a track, so narrow that there is no more than room to enable horses to pass along it--across the brink and along the side of a vast hollow, termed the ‘kettle.’ Following this rude track, the ‘Ketilstip,’ the summit of the range of hills, is reached which overlooks Krisuvik. In the midst of a green and extensive morass, interspersed with a few lakes, are caldrons of boiling mud, some of them fifteen feet in diameter, numberless jets of steam, and boiling mud issuing from the ground, in many instances to the height of six or eight feet. Sir George Mackenzie (who was accompanied by Sir Henry, then Doctor, Holland, now the President of the Royal Institution), in his justly-celebrated ‘Travels in Iceland, in 1810,’ gives a vivid word-picture of the scene. ‘It is impossible,’ he writes, ‘to convey adequate ideas of the wonders of its terrors. The sensation of a person, even of firm nerves, standing on a support which feebly sustains him, where literally fire and brimstone are in incessant action, having before his eyes tremendous proofs of what is going on beneath him, enveloped in thick vapours, his ears stunned with thundering noises--these can hardly be expressed in words, and can only be conceived by those who have experienced them.’[92]

“On the other side of the mountains subterranean heat is also manifested, and hot springs, accompanied by sulphur beds, are also found; but they have not been as thoroughly examined

OR

SULPHUR MOUNTAINS]

as those in the valley, and are represented as being less active.

“Mr Seymour, who has spent many months at Krisuvik, tells me that the sulphur beds on this side have been submerged by the clays washed down by the winter rains, and are, for the most part, now completely overgrown with grass. On digging beneath the surface, however, the sulphur earth is found to be only a short distance down, and on analysis the percentage of sulphur in one bed, 116 yards long, running up the side of the mountain, was discovered to range between 64 and 65·5. Here the earth was completely cold, and all further deposition of sulphur appeared to have ceased.

“In the valley itself the springs are not always visible at the surface, being so completely covered by the earth that it is only by piercing through the crust of indurated sulphur earth, that their presence is discovered. Sometimes the explorer is made unpleasantly aware of the insecure nature of his footing by falling through, and thus opening up a fresh thermal spring. The late Sir William Hooker, when visiting this place, in endeavouring to escape a sudden gust of strongly odorous vapour, jumped into a mass of semi-liquid hot earth and sulphur--and but for his presence of mind, in throwing himself flat upon the ground, would have sunk to a considerable depth; as it was, the difficulty of extricating himself was very considerable.

“The surface of the ground is covered in many places with a crust of two to three feet in depth of almost pure sulphur; and in the valley, where the steam jets are protected from the extreme violence of the wind, the sulphur is deposited tolerably evenly over the whole surface. If it were not for the ever-varying direction of the wind, the sulphur would, Captain Forbes is of opinion, be precipitated in regular banks, but it hardly ever falls for twenty-four hours in one direction, the wind capriciously distributing the shower in every direction.

“It has been suggested by those who wish to utilise the immense sulphur-producing power of this wonderful locality, that chambers should be erected (Sir George Mackenzie), or walls built up (Dr Perkins), by which means the force of the wind being broken, the sulphur would be quietly floated to the ground, instead of being carried up the sides of the hills, and thus more widely distributed.

“With little variation the general appearance of the ‘solfataras’ over the space of twenty-five miles along the volcanic diagonal is much alike: an elevation about two feet high and three feet in diameter, which is composed of a dark-bluish-black viscid clay, forms a complete circle round the mouth of a medium-sized spring. The water is sometimes quiescent, and sunk about two feet within the aperture; at other times it is ejected, with great hissing and roaring noise, to the height of from five to eight feet. At all times clouds of steam, strongly impregnated with sulphuretted hydrogen and sulphurous acid gas, issue from the orifice, both of which, during an eruption of the water, are greatly augmented in quantity. From the dark coloured and elevated margin of the fountain the yellow crust of crystallised sulphur extends a great distance in every direction. Columns of steam ascend from numberless points in the whole district, which are thus impregnated; and thus it is that, apparently for ages past, sulphur has been gradually heaped up in this locality till there are actually hills, which, as far as they have yet been pierced, show sulphur earth to be their main constituents. Hence they have acquired the name of the Sulphur Mountains.

“The soil is of different colours, but most generally white. It is, in the vicinity of the springs, a viscid earth, less plastic than clay, and more readily broken.

“When excavations are made into this earth, it is found to be composed of multitudinous layers, of different colours or shades of colour, each layer being quite distinctly divisible from those above and below it, though frequently no more than an inch or two in thickness.

“It is much to be regretted that the good example set by Olafsen and Povelsen of investigating the nature of the earth’s crust round about the solfataras, by piercing the soil, has not been more frequently carried out. In the summer of last year one of the suggestions which I made for the instruction of an expedition to this place, was that boring implements should be taken out and extensively used; but accident prevented the necessary appliances being forthcoming at the right time. I believe, however, that one of the chief features in the expedition which is to set out in March, will be the thorough examination, to as great a depth as practicable, of the strata in various parts of the Sulphur Valley.

“The spring chosen by Olafsen and Povelsen as the subject of their first experiment, was one which had made its appearance since the preceding winter, and which was just beginning to be surrounded by other mud springs and jets of steam. The ground was still covered with lovely verdure, and charming flowers were abundant, even at the very verge of the caldron of hideous hue and odour. A short distance from this opening they established their boring apparatus. The sequence of the layers was as follows:

“1. Three feet of reddish-brown earth, of a fatty consistence--of the ordinary temperature; at the bottom heat was perceptible to the touch.

“2. Two feet of a firmer kind of earth, nearly the same in colour as the first layer, unctuous to the touch.

“3. One foot of a lighter kind of soil.

“4. Five feet of a very fine earth of different colours, the first two feet being veined red and yellow, with streaks of blue, green, red, and white intermingled. The lower portion of this earth was somewhat firmer than that which covered it. The heat of this thick bed was so great that the soil extracted by the auger could not be handled until it had been for some time exposed to the air.

“5. One foot of a compact greyish-blue earth.

“6. In tapping this bed, which was four feet nine inches in thickness, and consequently at a depth of about twelve feet, water was first met with. It was found by comparison that the level of the water in the boiling mud spring coincided at this time with that of the water thus discovered. The heat was now very great, and a constant hissing and bubbling could be heard as proceeding from the bottom of the hole which had been made.

“7. Nine inches of greyish-blue earth.

“8. One foot six inches of a similar unctuous earth, containing many small white stones. This was the hottest layer of any yet pierced; the buzzing, humming noise was now much louder than before.

“9. Three feet of the same kind of clay, but much harder and more compact; this layer was also full of small, round, white stones.

“10. Six inches of a violet tinged earth, very greasy to the touch. In this bed the heat sensibly diminished.

“11. One foot six inches of red and blue clay intermingled. The heat continued to diminish very fast.

“12. One foot of reddish-looking clay, the temperature remaining about the same.

“13. Six inches of yellow and red clay.

“14. One foot of a greenish coloured earth, much less coherent than the previous layers. Here the heat again began to increase.

“15. One foot six inches of blue clay, filled with small pieces of white tufa. This bed was much hotter than either that above or that below it.

“16. One foot three inches of soft blue clay.

“17. Nine inches of an earth, easily pulverised when dry, which, whilst moist, was of a violet colour; on exposure to the air, however, this rapidly changed to a chocolate brown. The heat was again augmented as the centre of the bed was approached.

“At thirty-two feet the full length of the boring implements was used up; but from the set of the country in the vicinity, the experimenters believed they were close upon basaltic rock, when the heat probably ceased.

“In digging for the peculiar kind of brown coal which they call ‘surturbrand’ (a kind of fuel very much resembling Irish bog-oak, which can be used for like purposes), the inhabitants frequently go as deep as twenty-eight feet. They report that before reaching this depth they frequently pass through three or four beds of blue, yellow, and brown clay, and almost invariably find that the layers of blue clay are much hotter than any of the other strata.

“A second trial of the soil was made in the neighbourhood of some recent springs, farther to the east. The activity of the agencies at work here appeared to be greater than in the former case, and to have been longer in operation. The whole surface was thickly covered with sulphur, in a finely-divided state; there was much gypsum, and a large efflorescence of feathery alum. Thousands of very minute holes were discoverable on close examination, through which continuous jets of steam, sulphuretted hydrogen and sulphurous acid gases were emitted.

“An attempt was made to dig with spades; but the soil was found to be so hot, whilst the footing was at the same time so insecure, that it could not be persisted in. A spot some distance farther off was therefore pitched upon, where the earth was firmer and colder. The borer pierced through six feet of blue clay with great facility, the lowest portion being extremely hot. After this depth the earth became rapidly softer, at the depth of seven feet the same peculiar bubbling noise before noticed was heard. Continuing to bore, the bottom of the hole appeared to be in a state of ebullition, a boiling liquid being ejected in the narrow space around the handle of the auger with extraordinary violence, and no sooner was the tool withdrawn than a thick black fluid was ejected from the orifice to the height of several feet. A short time afterwards the jet ceased, the subterranean fire appeared to have expended its fury, but it soon recommenced with redoubled activity to dart forth fresh jets of steam and black, muddy water, continuing to boil and dance with but slight intermission. It appeared, therefore, evident that the result of this experiment was the premature formation of a fresh hot spring, which would otherwise have been, perhaps, a considerable time in forcing its way to the surface.

“It is somewhat to be regretted that no one amongst the numerous eminent men, men accustomed to experimental investigations and acute observers, who have since traversed this region, should have investigated the question of the origin of these hot springs and sulphur deposits from the point of view which was thus displayed by these careful and painstaking philosophers.

“The phlogistic theory being generally accepted in their day, and the chemistry of the earths and metals being in a very undeveloped state, we cannot now accept to its full extent the explanation they put forth of these phenomena; but the facts they disclose appear to me to be of the highest value, and to afford a clue which, if carefully followed, may lead to discoveries of much importance in the domain of volcanic energy.

“The conclusion they drew from their investigation is, that the hidden fires of Iceland dwell in the crust of the earth, and not in its interior; that the boiling springs and the mud caldrons certainly do not derive their heat from the depths of our globe, but that the fire which nourishes them is to be found frequently at only a few feet below the surface, in fermenting matters, which are deposited in certain strata.

“By their theory the gases from the more central parts of the earth penetrate these beds by subterranean channels, and so set up the chemical action, producing fermentation and heat, these channels also forming the means of intercommunication between the separate sites of activity, and equalising and transferring pressure.

“To return to their facts. They further observed that the heat is invariably found to be greatest in the blue and bluish-grey earth; that these earths almost always contain sulphuric acid; that they contain also sulphur, iron, alum, and gypsum; and lastly, that finely-divided particles of brass-coloured pyrites are visible throughout the whole of the beds when heat exists.

“Sulphuric acid is found in the hot beds above and below that which is the hottest, but this latter manifests no acidity that is sensible to the taste.

“Sulphuretted hydrogen is continually evolved from the clays containing the brass-coloured pyrites. Silver coins dropped into a hole made in these strata become rapidly reddened, and brass becomes quite black if held over it for a short time.

“Lastly, not only does the heat increase and diminish in various successive layers of the earth, in the neighbourhood of the active springs, but the locality of the heat, as might be expected from their previous observations, travels very considerably in different years.

“The solfatara of Krisuvik, with the mountains about it, is shown in the accompanying sketch by M. Eugène Roberts. It appears from afar to occupy the place of an ancient crater, but, as we have already seen, it is not near the crater, about the centre of the drawing, but at a considerable distance from the old volcanic centre, that the thermal springs and sulphurous exhalations have their present origin.

“Wherever they may have been previously, the springs are now situated between two mountains, the one Badstofer, on the right, originally composed of lava, the other, Vesturhals, on the left, of basaltic formation. Both, by the action of the thermal springs, are undergoing a process of disintegration and reconstruction.

“The kind of hills which form the solfataras, properly so called, increase in extent day by day; by the addition to the disintegrated rock of sulphur and of sulphurous and sulphuric acids.

“The yellow sulphur earth contains about four per cent. of free sulphuric acids; sometimes a little free hydrochloric acid, and a variety of sulphates, as might be supposed. Treated with distilled water, the filtered solution reddens litmus strongly; on addition of acetate of lead a flocculent precipitate is produced, which, when heated with carbon, disengages sulphurous acid.

“The sulphur is found in many different conditions, but for the most part in the same finely-divided, whitish-yellow form in which it is precipitated from sulphuretted hydrogen solutions. Where it assumes other states, crystallised in tears on the surface of the rocks, or coagulated in veins, it is on account of its having undergone subsequent heating. Of its primary origin by the decomposition of sulphuretted hydrogen, there is in my opinion no doubt.

“Professor Bunsen visited Krisuvik in 1845; his opinion is that sulphurous acid is evolved from the earth’s interior, which, oxidised either at the surface by the atmosphere, or at subterranean depths by atmospheric oxygen dissolved in cold water, is converted into sulphuric acid. The sulphuric acid thus generated is diffused among the constituents of the decomposed beds. This process represents the first stage of the fumerole action, which is manifested in the namar or solfatara of Krisuvik.

“Sulphur is now generally regarded as emanating from the stage of intermittent lethargy of a volcano, and the sulphides of iron, copper, arsenic, zinc, selenium, etc., fall in the same category as sulphur; they are secondary, not primary, formations. In the stage further off we have the host of sulphates produced by the oxidation of the sulphur into sulphuric acid, and its subsequent reaction on the metals and earths with which it becomes associated.

“The description of the Sicilian sulphur beds coincides so very exactly with that of the Icelandic mines, that one might pass very well for the other. D’Aubigny pictures nearly the whole of the central portion of Sicily as being occupied by a vast bed of blue clay or marl, in which are numerous and thick beds of gypsum and sulphur, and a combination of this mineral with iron and copper. The natural process by which they have been formed must, I think, be the same in each case. At Krisuvik copper has been found only in small quantities, but that is probably because it has not been sought for below the surface. Carbonate of copper, associated with sulphate of lime, is of frequent occurrence; and native copper has to a limited extent been discovered.

“A district in America, very similar in most of its characteristics, has recently been explored. The great hot-spring region of the sources of the Yellowstone and Missouri Rivers, in the United States, has, on account of the wonderful natural phenomena there manifested, been set apart by the United States Congress as a great national park for all time.

“The whole of this district is covered with rocks of volcanic origin of comparatively modern date. At present there are no signs of direct volcanic action going on, but the secondary kind of action, resulting probably as at Krisuvik, from the disintegration and decomposition of beds of volcanic origin, is in full progress. Boiling springs, mud-caldrons, and geysers are found in all parts of the region, and the description given by Mr V. Hayden, of the Yellowstone Lake and its vicinity, in every respect coincides with those of the geysers, mud-caldrons, and hot-springs of Iceland.

“In all cases there was found to be free access of water; free sulphur was widely dispersed, and the steam-jets were invariably accompanied by large quantities of sulphuretted hydrogen. The subterranean action in this country does not appear to have continued long enough to produce beds of sulphur and sulphur-earths, but has, nevertheless, been of sufficiently long standing to build up geyser tubes of so great a length that the internal pressure has formed other vents, rather than lift the immense column of water above it.

“The water of the springs contains sulphuretted hydrogen, lime, soda, alumina, and a slight amount of magnesia; some of these are only occasionally at the boiling point, and these, when the temperature is reduced below 150° Fahr., deposit great quantities of the sesquioxide of iron, which lines the insides of the funnels, and covers the surface of the ground wherever the water flows. If the reaction consists in the decomposition of iron pyrites, and the sulphur is carried sufficiently far off to prevent its re-combination with the iron to form iron sulphate, the formation of the iron sesquioxide is fully accounted for.

“As a rule, the groups of hot springs are, as in Iceland, in the lower valleys, and either along the margins of streams, or nearly on a level with them. The grand area where they occur is within the drainage of the Yellowstone, where a space of forty miles in length, with an average width of fifteen miles, is either at the present time, or has been in the past, occupied by hot springs.

“That the quantity of sulphuric acid here produced is very large, is proved by the immense quantity of alum which is found, for the streams, the mud, the earth are thoroughly impregnated with it. The funnel-shaped craters from which the boiling mud is ejected, are so similar to those of the Krisuvik that the figure on page 140 will answer for both places. The circular rim varies from a few inches to several feet in diameter. Sometimes these are clustered close together, yet each one being separate and distinct from the others.

“The foregoing are the most prominent facts connected with the development of sulphur from the earth in the elementary state. The full explanation of all the phenomena accompanying it appears to me to be the key by which the great secret of volcanic energy may he ultimately unlocked. At present it appears to be doubtful whether the sulphur results from the decomposition of metallic sulphides, by heat and water combined, or by sulphuric acid formed by the oxidation of sulphurous acid. In the one case, the whole action is so far within our reach, that it should not be an insurmountable difficulty to establish the point as to whether the whole action does not depend on the percolation of water into beds of pyrites surrounded by other beds which are non-conductors of heat.

“The other view, viz., that the sulphur proceeds as sulphurous acid from a lower depth, is on account of the more complicated action required, far from being as satisfactory to my mind as the more simple supposition above.

“Until boring experiments have been made, conducted with great care, and to considerable depths, no positive conclusion can be arrived at. It is also an element in the question of much importance, to discover whether the beds penetrated by the water are already heated, whether the water is heated before it reaches the sulphur-bearing strata (the clays containing pyrites), or whether both are not alike cold till they have been for some time in contact.

“Less than a quarter of a mile from the hot springs is a lake, Geslravatn, formed by the filling up of an extinct crater. This the inhabitants describe as being fathomless (Mr Seymour, last year, found no bottom at five and twenty fathoms). The depth is, at any rate, very considerable. Although so close to a spot where the ground is, even at the surface, scorching to the feet, the water in this lake is ice-cold. Sir George Mackenzie also remarked a somewhat similar fact. On the side of the Sulphur Mountain, amidst the seething, steaming hills of almost burning earth, a spring of clear cold water was met with. To my mind these facts are most in accordance with the view that the action is local and self-dependent.

“The Krisuvik sulphur mines have been worked at various times, but want of proper roads, and ignorance of the proper method of extracting and refining the sulphur, have prevented their proper development. The Sicilian mines can be worked at a considerable profit, where, more than 390 feet below the surface, beds are met with containing only 15 per cent. of sulphur. At Krisuvik, absolutely on the surface, clays are met with which contain from 15 to 90 per cent. of sulphur. Under proper and careful supervision, their future should be prosperous.

“Two German gentlemen, under the auspices of the Danish Government, worked these mines in the early part of the last century, and so much was exported to Copenhagen during the time the excavations were carried on, that a sufficiently large stock was laid up to serve the consumption of Denmark and Norway from 1729 to 1753.

“Horrebow describes the sulphur mines as being actively worked from 1722 to 1728, to the great advantage of the inhabitants, who reaped much profit from its extraction.

“By his account of their mode of prosecuting this enterprise, the sulphur does not appear to have been refined in the island, but exported in its crude state. The less active mines were chosen for cutting into. He says: There is always a layer of barren earth upon the sulphur, which is of several colours, white, yellow, green, red, and blue. When this is removed, the sulphur earth is discovered, and may be taken up with shovels. By digging three feet down, the sulphur is found in proper order. They seldom dig deeper, because the place is generally too hot, and requires too much labour, also because sulphur may be had at an easier rate, and in greater plenty, in the proper places. Fourscore horses may be loaded in an hour’s time, each horse carrying 250 lbs. weight. The best veins of sulphur are known by a kind of bank or rising in the ground, which is cracked in the middle. From hence a thick vapour issues, and a greater heat is felt than in any other part. These are the places they choose for digging, and after removing a layer or two of earth, they come to the sulphur, which they find best just under the rising of the ground, when it (the sulphur) looks just like sugar candy. The farther from the middle of the bank, the more it crumbles, at last appearing as mere dust. But the middle of the bank is an entire hard lump, and is with difficulty broken through. The brimstone, when first taken out, is so hot that it can hardly be handled, but grows cooler by degrees.

“In two or three years these veins are again filled with sulphur. The death of the person at Copenhagen who had the sole and exclusive privilege of exporting sulphur from Iceland put an end to what had promised to be a very thriving industry. The inhabitants continued to collect the sulphur earth for some time after its exportation had ceased; and many of them lost considerably by it, large quantities having been gathered which they were never able to dispose of.

“According to Dr Perkins, the sulphur mines were again worked by the Danish Government for fifteen years, but the method of purifying adopted was very imperfect. The sulphur earth was heated in iron boilers, and when the sulphur was melted, fish oil was added, and the whole mass stirred up. On allowing the mixture to stand for a time, the earthy matter formed a soap on the top of the molten mass; this being removed, tolerably pure sulphur remained behind.

“In 1832, these mines were visited by K. von Nidda, the celebrated geologist, by whose advice a Danish merchant, named Kenidzon, purchased them. He only worked them for a short period. The sulphur earth was collected without much regard being paid to the relative richness of the beds. It was taken on the backs of horses to Havnafiord, and thence shipped to Copenhagen. The cost of transport brought the sulphur to too high a price to render the undertaking successful.

“In 1857, political matters caused the attention of Her Majesty’s Government to be directed to finding a new source of sulphur supply. Commander J. E. Commerell, of her Majesty’s ship ‘Snake,’ was sent to Iceland by the Lords Commissioners of the Admiralty, to visit and report upon the capabilities of the mines of Krisuvik and Husavik. He found that the nearest safe port to the Krisuvik beds was Havnafiord; this port is fourteen miles from the sulphur beds by the present roads, and nine miles from Reikjavik. The harbour is well sheltered, with good anchorage of seven or eight fathoms three cables’ length from the beach; it at present enjoys as much traffic as Reikjavik. The road from Krisuvik might be much shortened, and a tramway might also he laid down. During the past year a survey has been made, and plans drawn for a railway or tramway to Havnafiord.

“The actual extent of the sulphur beds it is quite impossible to calculate; forty-seven have been already discovered. The deposit of sulphur Commander Commerell personally saw he describes as amounting to many thousands of tons, and, all the mines being in what is called a ‘living’ state, the sulphur taken away is reproduced in two or three years. He considers that sulphur in a pure state could be shipped at Havnafiord for £1 per ton.

“The sulphur at Myvatn, though great in quantity, is, he considers, at too great a distance from a port of embarkation to permit its extraction being carried on with any chance of competing with that from the Krisuvik mines.

“No further steps were taken in the matter by the British Government, the political complications which led to the expedition having been removed; but the attention of English merchants having been drawn to these rich deposits by the highly favourable character of Commander Cornmerell’s remarks, renewed attempts are being made to render commercially available the immense sulphur-producing power which the Krisuvik solfataras undoubtedly possess. To some of these gentlemen I am greatly indebted for much valuable information, put at my disposal for the purposes of this paper, and amongst them I have specially to tender my thanks to Mr Ramsdale and Messrs Thorne, of Gracechurch Street, and particularly for the use of numerous and carefully-selected samples of the sulphur earths which were freely placed at my disposal. These samples I hope to make the subject of a future paper.

“Since writing the foregoing paper, I mentioned, in the course of conversation with Sir Henry Holland, the conclusions which are derived from the examination of all the trustworthy facts relating to the sulphur deposits. This led him to examine entries in his unpublished diary, made at Krisuvik in 1810. The theory which he then conceived so thoroughly agrees with all that has been learnt respecting the phenomena in question, that I, with his kind permission, print an extract from his note-book:

“‘The theory of these sulphureous springs (if springs they may be termed) at Krisuvik is an interesting object of inquiry. They are situated in a country decidedly of volcanic origin. The high ground on which they appear is composed principally of the conglomerate or volcanic tufa, which has before been noticed. The source of the heat which can generate permanently so enormous a quantity of steam must, doubtless, reside below this rock; whether it be the same which produces the volcanic phenomena may be doubted, at least if the Wernerian theory of volcanoes be admitted. It certainly seems most probable that the appearances depend upon the action of water on vast beds of pyrites. The heat produced by this action is sufficient to raise an additional quantity of water in the form of steam, which makes its way to the surface, and is there emitted through the different clefts in the rocks. The sulphates of lime and alumina, appearing upon the surface, are doubtless produced, in process of time, by these operations. In corroboration of this view, it may be observed that the quantity of steam issuing from the springs at Krisuvik is always greater after a long continuance of wet weather, and that whenever earthquakes occur on this spot, it is during the prevalence of weather of this kind.’

“The learned and now aged author expressed the highest gratification that the views which he formed at twenty-two years of age should possess so much value so many years after.”

* * * * *

The visit of the two engineers, Messrs Shields & Gale, has also been elsewhere alluded to. Finally, Mr R. M. Smith informs me that the prospects of the Krísuvík diggings now look brighter. The project of tramways, or locomotives, seems to have been abandoned in favour of carts and ponies plying on a good road, about sixteen miles long, between the Sulphur Mountain and Hafnafjörð.