# Transactions of the Geological Society, 1st series, vol. 2/On the Island of Teneriffe

XII. Some account of the Island of Teneriffe.
THE island of Teneriffe is the principal island of the seven in the Western Ocean, that are called generally by the name of the Canaries. It lies north-east by south-west, and is in length from the Punta del Hidalgo to the Montana Roxa, its northern and southern extremities, about 70 English miles; its greatest breadth not exceeding 30. The superficies may be considered as containing 80 square leagues.
The island narrows at its north-eastern and widens considerably at its south-western extremity. About the centre of the latter, or perhaps to describe more accurately, to the westward of the central point, is the mountain called by the Spaniards el Pico di Tiéde, but better known by the name of the Peak of Teneriffe, and which is the highest land not only in the island, but in all the Canaries; the mean of various observations making it 12,500 feet above the level of the sea. It is visible at a great distance; we saw it perfectly distinct thirty-four leagues off by chronometrical observation, when it appeared rising like a cone from the bed of the ocean; and I have heard that it has been clearly distinguished at a distance of 45 leagues.
The rocks and strata of the Island of Teneriffe are wholly volcanic; a long chain of mountains, which may be termed the central chain, traverses the island from the foot of the second region of the ​Peak sloping down on the eastern, western, and northern sides, to the sea. Towards the south, or more properly the S.S.W. the mountains are nearly perpendicular, and, though broken into ridges and occasionally separated by deep ravines that are cut transversely as well as longitudinally, there are none of those plains nor that gradual declination of strata that the south-eastern and north-western sides of the island exhibit.
From the Barranco Seco, in the neighbourhood of Santa Cruz, to the northerly point called Punta del Hidalgo, a series of steep and abrupt mountains form headlands to the sea, separated from the central chain by the valley of Laguna; these mountains are rugged and peaked, drawn up, if the term may be used, in a column, and are divided by deep ravines. The sides of these mountains are steep, being in many places cut nearly perpendicular to the horizon, and are all composed of lava generally of the basaltic formation, mixed with beds of tufa and pumice. From Hidalgo point to that of Teno, the most westerly point of the island, the strata vary from beds of pumice and decomposed lava and ash, which form the plains of Laguna Ticaronte and Songal, to streams and currents and headlands of lava, similar to those of the Barranco Hundo, San Ursula, Las Horcas, and Las Guanchas. The slope from the central chain is here gradual, intersected by ravines and streams of lava. The soil famed for its fertility and which produces the Teneriffe wine, is composed of lava and ash in a state of decomposition. Headlands, some of them from two to three hundred feet in height, project into the sea between San Ursula and Orotava, forming perpendicular cliffs. At the western extremity of the island from Punta di Teno to Puerto de los Christianos, the strata rise in a broken ridge to the Peak, the land ascending gradually from Punta de Teno by a chain of small peaked hills; the ​point itself being very low and projecting as a promontory into the sea. The declination of the strata is similar from the Peak to Puerto de los Christianos. This south-westerly chain is broken into many abrupt ridges, and is cut nearly perpendicular down to the sea. I could not perceive any base or shelf as on the other sides of the Peak, from which the cone arose, but the fall is regular though steep. From Puerto de los Christianos to Santa Cruz, comprising the southern and south-eastern sides of the island, the form is similar so that in the vicinity of Orotava, but it is barren and desolate, laid warm by screams of lava. In the short space of a few leagues I counted no less than seven cones of extinct volcanoes, and the country is covered with scoria, exhibiting no appearance of culture, and hardly any vegetation; it is more broken into ravines and more intersected by lava torrents than on any of the other sides of the island. Numerous peaked and conical mountains rise upon the slope of the chain, and the whole country is covered by scoria, and is one continued stream of lava. The Montana Roxa itself is a singular example of the dislocation of strata so commonly found in countries of volcanic formation; it is evidently a slip or fall of semi-columnar lava, and slopes into the sea at an highly inclined angle.
The ordinary strata of the island are as follows, reckoning from below upwards: 1st. the porphyritic lava covered by scoria and sometimes by pumice. This lava is composed of hornblende and feldspar, and contains no other substance. The next stratum graduates into what the Spaniards call Roccaverde or greenstone, and is composed of feldspar and hornblende; upon this is generally a thick stratum of pumice, and last of all towards the surface is the basaltic lava covered also by tufa and ash. This lava decomposes the soonest. It also contains the greatest variety of extraneous substances, and is sometimes divided by a layer of large crystals of olivine some inches ​long, and towards the north-east is often intersected by strata of porphyritic slate. These lavas are more earthy and cellular than those which I have had an opportunity of observing elsewhere, yet they contain fewer extraneous substances than those of Ætna and Vesuvius; they are in some places exposed to view in the vallies similar to those of the Corral in the island of Madeira. The valley of Las Guanchas on the north-west side of the Peak, contains according to M. Escolar above 100 strata of lava, the one reposing upon the other, at times alternating with pumice and tufa. The depth of these strata varies. M. Escolar has seen one of basaltic lava between 100 and 150 feet in depth in one solid mass, cellular at the surface, but gradually becoming more compact towards the bottom. This basaltic lava contains olivine and hornblende, and, in the caves on the coast, zeolite. This substance is also found in stalactites and in masses, sometimes in layers spread between the strata and diffused over the rock.
Nodules of chalcedony are sometimes also found, but these substances occur only in the chain of mountains towards the north-east, from the northern extremity of Santa Cruz to the point of Hidalgo.
The lavas of the island are of an endless variety, and the number of streams that have flowed are much beyond all enumeration. The whole surface is either ash, or solid or decomposed lava, which seems again and again to have been perforated by volcanic eruptions; the number of small extinct volcanoes is prodigious, they are to be found in all parts of the island, but the stream that has flowed from even the largest of them, such as the lava of the Peak called el Mal Pais, is trifling in comparison with that immense mass of lava mountains ​which constitute the central chain of the island, and which stretch out as headlands like those of las Horcas and San Ursula.
I never found in situ those masses of columnar basaltic rock that are so common in the island of Madeira: but in the valley of las Esperanzas, in the chain of hills to the north-eastward of the town of Santa Cruz, they lie scattered about in considerable numbers, and M. Escolar told me that he had seen strata of them to a considerable extent, exhibiting with precision the columnar basaltic form; the modern lavas of the peak are all basaltic, that of 1704 is decidedly so, as well as that of 1798, though not exhibiting any prismatic form. Prisms of basaltic lava are yet found on the peak: I picked up one, though there are no strata of them to be met with. The metals are rare, and afford but little variety: specular and micaceous iron, black and grey manganese are all that have hitherto been discovered. The salts that are so common on Vesuvius, are here seldom met with. Augite is also rare, and mica and leucite, though carefully sought after, have hitherto not been found.
In that part of the island between Laguna and Tacaronte, where there are few streams of lava, the soil is evidently volcanic. I examined many of the clods that were turned up by the plough, and found them all alike: they contained much strong clay, with crystals of feldspar, olivine, and specular iron. Dr. Gillan, who accompanied Mr. Barrow and Sir G. Staunton, has advanced an opinion, that between Laguna and Matanzos there are no signs of volcanic formation. That the currents of lava occur but seldom is most true; but the mountains in the vicinity of Laguna are all volcanic, and one has a visible crater; besides, the assertion would prove too much; for it would go to maintain that the Campagna Felice, as well as the plains of Catania, were not created by the ​ash and pumice eruption of Vesuvius and Ætna. The bed of soil is here very deep. I examined some ravines that the rains had laid open to the depth of 30 or 40 feet: the strata were indurated at the bottom, and resembled the tufa in the vicinity of Naples, and all contained the substances mentioned above. This tufaceous character changes as you ascend the hill that separates Laguna from Santa Cruz; the hill itself, and the whole neighbourhood of the latter city is one continued stream of lava, hardly at all decomposed, with little or no vegetation; but here and there in the hollows some few stunted plants of the aloe algarvensis, and the cytisus.
Having given a general account of the island, I shall now attempt to describe the country of the peak, which mountain ascended on the 16th of September, 1810. The road from Puerto Orotava to the city of Orotava, is a gradual and easy slope for three or four miles, through a highly cultivated country. The soil is composed of volcanic ash and earth, and to the eastward of the town of Puerto di Orotava are the remains of a recent volcano, the crater and cone being distinctly visible. Leaving the town of Orotava, after a steep ascent of about an hour through a deep ravine, we quitted the cultivated part of the slope or valley, and entered into a forest of chesnuts; the trees are here of a large size. This forest of chesnuts is mixed with the erica arborea, or tree heath, which shrub rises to the height of 18 or 20 feet. Some of the stems are as thick as the arm of a man, joined together in bunches or tufts like the common heath. The form of this forest is oblong, it covers the flank of those hills which I have already denominated the central chain, from their summit to half their elevation from the plain. The soil here is deep, and formed of decomposed lava, small ash, and pumice. I examined several channels in the strata or ravines ​worn by the rains, and there was no appearance of any other rock. Leaving this forest, the track passes over a series of green hills which we traversed in about two hours, and at last halted to water our mules at a spot called el barranco del pino de la meruenda, where there is a small spring of bad and brackish water issuing from a lava rock. The ravine is of considerable depth. After the vegetable earth, which is 2 or 3 feet deep, a layer of tufa succeeds, which is followed by a lava of a greyish-blue colour, 30 or 40 feet in depth. It is compact, contains olivine, and the strata lap over each other, but shew no appearance of columnar formation. The range of green hills extends a mile or two further, the soil shallowing by degrees, more lava and scoria shewing themselves on the surface, the ravines or channels, worn by the rains, becoming more common, the trees and shrubs gradually dwindling in size, and of them all the Spanish broom alone at length covers the ground. Leaving behind us this range of green hills, the track still ascending leads for several hours across a steep and difficult mass of lava rock, broken here and there into strange and fantastic forms, worn into deep ravines, and scantily covered in places by a thin layer of yellow pumice. The surface of the country, for miles and miles around, is one continuous stream of lava; the rents or ravines of which seem to be formed partly by the torrents from the hills flowing for so many ages, and partly from that tendency, characteristic of a lava current, to keep itself up in embankments, and in its cooling process to open out into those hollows which I have uniformly found in every eruption of lava that I have had an opportunity of examining. This lava is cellular beyond any I have ever seen, is of a clayey earthy porphyritic composition, and contains few, if any, pieces of olivine, though here and there felspar in a semicrystallised form. As we proceeded on our road, the hills on our left, though broken at ​times in deep ravines, gradually rose in height till the summits were lost in those of the central chain, while on our right we were rapidly gaining an elevation above the lower range of the peak. This range forms one flank of the plain or valley of Oratava, stretching from south-east to north-west, and is broken into steep precipices, cut down in some places perpendicular to the horizon, and called las Horcas: it joins the central chain at the high elevation of the pumice plains, sweeps down the side of the valley, and forms a headland near 200 feet high, projecting into the sea, some miles from Oratava; we traversed this country an hour or two, till we reached the point of intersection of las Horcas with the plains of pumice. On the road are several small conical hills or mouths of extinct volcanoes, the decomposed lava on the edges of these craters having a strong red ochreous tint; by degrees the lava becomes more and more covered by a small ash, and the masses or heaps of pumice gradually increase, till the surface is completely concealed. At length an immense undulated plain spreads itself like a fan, on all sides, nearly as far as the eye can reach, and this plain is bounded on the west south-west, and south south-west, by the regions of the peak; and on the east and north-east by a range of steep perpendicular precipices and mountains, many leagues in circumference, called by the Spaniards Las Faldas. M. Escolar informed me that the wall could be traced for many leagues, the whole circumference of which evidently formed the side of an immense crater. This tract, called Las Canales, contains, according to the same authority, 12 square leagues. As we entered this plain from the south-west, there are to be seen several declivities of lava and strata, broken inwards towards the plain, and evidently a continuation of the above mentioned line of wall and the remains of the original crater. There ​is here no appearance of columnar formation, the lava being earthy and porphyritic; this continuity of wall, at present so easy to be traced, may be considered as forming the sides of one immense crater, from which perhaps originally the lavas of the island flowed, which might have thrown up the cone of the peak, and covered these wide-spreading plains or clanuras with the deep beds of ashes and pumice. On this plain or desart, for we had long left all shew of vegetation, except a few stunted plants of Spanish broom, a sensible change was felt in the atmosphere; the wind was keen and sharp, and the climate like that of England in the months of autumn. All here was sad, silent, and solitary. We saw at a distance the fertile plains on the coast, lying as it were under our feet, and affording a cheerful contrast to the scenes of desolation with which we were surrounded; we were already 7 or 8000 feet above the level of the sea, and had reached the bottom of the second region of the peak. Immense masses of lava, some of them many hundred tons in weight, lie scattered on these pumice plains. Some are broken by their fall, and all wear the appearance of having been projected by volcanic force. Their composition is uniformly porphyritic, with large masses of feldspar; the whole compact and heavy, and bearing no resemblance to the earthy lava we had seen in such abundance prior to our entering these pumice plains. Many of these masses are completely vitrified, while others only shew marks of incipient vitrification; but from their site and fracture, from the insulated state in which they lie, from there being no appearance of lava in a stream, from the pumice bed being very deep, (and in one place I saw it exposed to a depth of between 20 and 30 feet) from all these facts taken together, there can be little doubt that these masses were thrown out of the mountain when that lava flowed, which is of similar substance, and which is called by the Spaniards El Mal Pais.
​Having reached the end of the plain we found ourselves at the bottom of a steep hill, at the foot of which is a mass or current of lava which has flowed from the higher regions of the peak, and which constitutes the eastern branch of the lava of Mal Pais. We began to ascend this steep and rapid part of the mountain which is composed of a small white or yellowish ash mixed with masses of pumice and fragments of lava similar to that found in the plains, of which several small pieces that I picked up were in a state of vitrification. After a laborious not to say hazardous ascent of about an hour, the pumice and ash giving way and the mule sinking knee deep at each step, we arrived at about five in the afternoon at the other extremity of the stream of lava, which descending from the summit of the second region of the peak divides at the foot of the cone into two branches, the one running to the north-east and the other to the north-north-west; at the extremity of this latter are several immense blocks or masses of lava which bear the name of La Estancia di los Ingleses, and are rocks, not caves as has been stated by some writers. It was here we were to pass the night, so, lighting a fire made of the dry branches of the Spanish broom and stretching part of a sail over a portion of the rock, we ate our dinner and laid ourselves down to sleep. I however passed the best part of the night by the fire, the weather being piercing cold; as I stood by the fire the view all around me was wild and terrific, the moon rose about ten at night, and though in her third quarter gave sufficient light to shew the waste and wilderness by which we were surrounded: the peak and the upper regions which we had yet to ascend towered awfully above our heads, while below, the mountains that had appeared of such a height in the morning and had cost us a day's labour to climb, lay stretched as plains at our feet; from the uncommon rarity of the atmosphere the whole ​vault of heaven appeared studded with innumerable stars, while the valleys of Orotava were hidden from our view by a thin veil of light fleecy clouds, that floated far beneath the elevated spot we had chosen for our resting place; the solemn stillness of the night was only interrupted by the crackling of the fire round which we stood, and by the whistling of the wind, which coming in hollow gusts from the mountain, resembled the roar of distant cannon.
Between two and three in the morning we resumed on foot our ascent of the same pumice mountain, the lower part of which we had climbed on horse-back the preceding evening; the ascent became however much more rapid and difficult, our feet sinking deep in the ashes at every step. From the uncommon sharpness of the acclivity we were obliged to stop often to take breath; after several halts we at last reached the head of the pumice hill at its point of intersection with the two streams of lava, the direction of which I have before described. This is the commencement of that division of the mountain called el Mal Pais; after resting some short time here, we began to climb the stream of lava stepping from mass to mass, the ascent is steep, painful and hazardous, in some places the stream of lava is heaped up in dykes or embankments, and we were often obliged to clamber over them as one ascends a steep wall, this lava is of the same porphyritic appearance as the masses we found in the plains, it is not covered with a thick scoria, and seems never to have been in a very fluid state, but to have rolled along in large masses. The felspar is crystallized in the lava itself, which is slightly cellular at its surface, yet though I searched carefully I was unable to discover any extraneous substance. The whole composition of the stream seems to be felspar imbedded in a brown clayey paste, remarkably hard, of a close texture and heavy; judging from the sharp declivity of the mountain it appears ​surprising that the lava should have flowed so short a distance; as it does not exceed 21/2 or three miles from the base of the cone to the point of union with the pumice hill; the mass of lava as well as its depth is prodigious; M. Escolar told me that its greatest breadth was above two miles, its depth it is not easy to determine, there are however several ravines or valleys in the course of the stream, some of which may be from 60 to 100 feet deep. The fusion of the mass does not appear to have been perfect; it is very earthy, and though vitrified pieces are found, there is no general appearance of vitrification; there are some pieces that exhibit an union with the pumice and the gradation from the stony structure to the vitrified, and thence to pumice. Immense heaps of this latter lie scattered on the surface of the lava, some of them containing large crystals of felspar, which abounds in, or more properly forms the constituent part, of the lava of the Mal Pais.
We halted several times during the ascent, and at last reached a spot called La Cueva, one of the numerous caves that are found on the sides of the mountain; this is the largest of them, and is filled with snow and the most delicious water, which was just at the point of congelation, the descent into it is difficult it being thirty or forty feet deep. One of our party let himself down by a rope, he could not see the extent of the cave, but the guides declared it to be 300 feet in length and to contain thirty or forty feet of water in depth, the roof and sides are composed of a fine stalactitic lava similar to that found on Vesuvius, and it is of the same nature as that which flowed on the surface. We rested here about half an hour, during which we had an opportunity of observing the rising of the sun and that singular and rapid change of night into day, the consequence of almost an entire absence of twilight. As we ascended the north-east side of the mountain this view was strikingly beautiful, ​at first there appeared a bright streak of red on the horizon, which gradually spread itself, lighting up the heavens by degrees, and growing brighter and brighter till at last the sun burst forth from the bed of the ocean, gilding as it rose the mountains of Teneriffe and those of the great Canary; in a short time the whole country to the eastward lay spread out as a map, the great Canary was easily to be distinguished and its rugged and mountainous character, similar to that of the other islands, became visible to the naked eye. The cold at this time was intense, the wind keen and strong, and the thermometer sunk to 32 degrees; after a short though rapid ascent we reached the summit of the second stage of the mountain, we passed over a small plain of white pumice on which were spread masses of lava, and at length arrived at the foot of the cone. This division of the mountain forms what is generally termed the Peak of Teneriffe; it resembles the present crater of Vesuvius, with this difference, however, that while the surface of that mountain is composed of a black cinder or ash, the superficies of this appears to be a deposit of pumice of a white colour, of scoria and of lava, with here and there considerable masses that were probably thrown out when the volcano was in action. Towards the north-west on the right hand of our ascent, there is a small current of lava shewing itself above the pumice, the composition of which is similar to that at the bottom, though of a redder tinge; it is broken on the surface and is in a rapid state of decomposition. Numerous small cavities on the side of the mountain emitted vapour with considerable heat. Here begins, in my opinion, the only fatiguing part of the ascent; the steepness of the cone is excessive, at each step our feet sunk into the ash, and large masses of pumice and lava rolled down from above; we were all bruised and our fleet and legs were cut, but none materially hurt; at last we ​surmounted all difficulties and seated ourselves on the highest ridge of the mountain. This uppermost region does not appear to contain in superficies more than an acre and an half, it is composed of a lava similar to that on its sides, though decomposed and changed white or grey by the action of the sulphurous acid; this acre and an half is itself a small crater, the walls of which are the different points on which we sat, and are plainly visible from below. Within, the lava is in the most rapid state of decomposition; losing its brown colour and shade of red, and acquiring a whitish grey almost the colour of chalk; large masses of sulphur are depositing, which are crystallized in minute though distinct forms; there is also a coating of alum produced by the union of the sulphurous acid with the argil of the lava; the surface is hot to the feet and the guides said it was dangerous to remain long in one spot; as it was, some of us sunk to our knees in the hot deposit of sulphur; upon striking the ground with the feet the sound is hollow, similar to what is produced by the same impulsion on the craters of Vesuvius and Solfaterra. I estimate the depth of the crater to be, from the highest ridge to the bottom, about 200 feet forming an easy and gradual descent, the whole being in a state of rapid decomposition, and charged with sulphur, large masses of which are every where depositing. I searched in vain, for any of the arseniate so common on Vesuvius, nor could I find those siliceous stalactites resembling strung pearls, which are met with in the island of Ischia, in the crater of the Solfaterra, and in the Maremma of Tuscany. The sulphur is pure and fine, and is sold for a considerable price at Orotava. We were not able to go all round the walls or exterior summit of the crater, and hence could not distinguish its southern or western declivity; M. Escolar assured me they are similar to, though more rapid than the side by ​which we ascended; from this side flowed the basaltic lavas of 1704, and of the last eruption in 1797; this latter stream of lava flowed in a remarkably slow current, for notwithstanding the sharp descent of the mountain, and the length of the lava not exceeding three miles, several days elapsed before it reached the spot where it stopped; how little fluid this lava must have been is evident, when it is remembered that the lava of Vesuvius in 1794, which destroyed Torre del Greco, reached the sea from the bottom of the cone, a distance of eight miles, in little more than six hours. M. Escolar further told me that there is on this south-western side of the Peak an ancient lava, at present not at all decomposed, of several miles in length, and in a perfect state of vitrification; the whole of this stream has the appearance of obsidian. All these lavas appear to have flowed from the bottom of the cone, and to have run from its base in the same manner as that of Vesuvius in 1794, the crater of which vomited out ash and pumice, and large pieces of rock, while the current of lava issued from its side. It is not however improbable that the cone itself is of anterior formation to this vitrified lava, as the summit of the Peak is similar to the lava of the Mal Pais, and that being porphyritic is considered as of more ancient date than the one above mentioned, which is basaltic.
If one might hazard a conjecture upon a subject where the data are so few, I should be inclined to suspect that the Peak itself, as well as the whole of the country around it which forms its base, were produced by that immense crater called Las Canales, the shape and magnitude of which I have before taken notice of when traversing the pumice plains; it is also well worthy of remark that there is no volcano in action at all to be compared in size of crater to those that are extinct. The ancient crater of Vesuvius is considerably ​larger than the present, and those in the vicinity of Naples, the eruptions of which probably created that district of Italy, are of enormous extent. The crater of the Camaldoli is somewhat more than two leagues in circumference, and the superficies of the Canales is estimated at 12 square leagues. These vast craters were probably capable of ejecting from their bosom those stupendous beds of lava, which being so much more extensive than any that have flowed from more recent eruptions have led some persons to deny the former to be the effects of a central fire. That all the Island of Teneriffe was volcanically produced no man who examines it can have any doubt, and though the smallness of the existing crater of the Peak may lead one to imagine that it alone could not be the effective cause of all the phenomena, yet the innumerable volcanoes on all sides of the island, the appearance of Las Canales, and its elevation, are able to account for the extent of the streams and beds of lava and of the deposits of tufa and pumice, of which the island is composed. Having no data to proceed upon but what is given by the measurement of the eye, it is not easy to determine the magnitude of the cone at its base; one may say at a venture, it is about three miles in circumference, though towards the S.S.W. the descent is much more abrupt, and the plain from which the cone springs not perceptible. The view from the summit is stupendous, we could plainly discover the whole form of the island, and we made out distinctly three or four of the islands, which together are called the Canaries; we could not however see Lancerotte or Fuerteventura, though we were told that other travellers had distinguished them all.
From this spot the central chain of mountains that runs from south-west to north-east is easily to be distinguished. These with the succession of fertile and woody vallies, commencing from San Ursula and ending at Las Horcas, with the long line of precipitous lava rocks ​that lay on the right of our ascent, and which traverse that part of the island, running from east to west from their point of departure at the Canales to where they end in an abrupt headland on the coast, with their forests and villages and vinyards, the port with the shipping in the roads, the towns of Orotava with their spires glittering as the morning sun burst upon them, afforded a chearful contrast to the streams of lava, the mounds of ash and pumice, and the sulphurated rock on which we had taken our seat. The sensation of extreme height was in fact one of the most extraordinary I ever felt, and though I did not find the pain in my chest arising from the rarity of the atmosphere, near so acute as on the mountains of Switzerland, yet there was a keenness in the air independent of the cold that created no small uneasiness in the lungs. The respiration became short and quick, and repeated halts were found necessary. The idea also of extreme height was to me more determinate and precise than on the mountains of Switzerland; and though the immediate objects of vision were not so numerous, yet as the ascent is more rapid, the declivity sharper, and there is here no mountain like Mont Blanc towering above you, the 12,000 feet above the level of the sea appeared considerably more than a similar elevation above the lake of Geneva. We remained at the summit about three-quarters of an hour, our ascent had cost us a labour of four hours, as we left the Estancia at ten minutes before three and reached the top of the peak before seven; many indeed of our halts were needless, and M. Escolar told me that he had twice ascended to the summit in somewhat less than three hours. Our thermometer which was graduated to the scale of Fahrenheit was during our ascent as follows: at Orotava at eight in the morning, 74°; at six in the evening at La Estancia, 50°; at one in the following morning 42°; at La Cueva at half-past ​four 32°, at the bottom of the cone 36°; at the top of the Peak one hour and a half after sun-rise 38°. The descent down the cone is difficult from its extreme rapidity, and from the fall of large stones which loosen themselves from the beds of pumice. Having at last scrambled to the bottom, we pursued our march down the other course of the lava, that is to say down its westerly side, having ascended its eastern. The ravines and rents in this stream of lava are deeper and more formidable; the descent into them was always painful and troublesome, often dangerous, in some places we let ourselves down from rock to rock. I can form no opinion why there should be these strange irregularities in the surface of this lava; in places it resembles what sailors term the trough of the sea, and I can compare it to nothing but as if the sea in a storm had by some force become on a sudden stationary, the waves retaining their swell. As we again approached La Cueva there is a singular steep valley, the depth of which from its two walls cannot be less than 100 to 150 feet, the lava lying in broken ridges one upon the other similar to the masses of granite rock that time and decay have tumbled down from the top of the Alps; and, except from the scoria or what Milton calls “the Fiery Surge,” they in no degree bear the marks of having rolled as a stream of liquid matter. This current like that of the eastward branch has no resemblance to any lavas I have seen elsewhere, it is hardly at all decomposed, full of laminæ of feldspar, the fracture conchoidal, and the texture porphyritic, the colour brown like that of the other branch; it is but slightly cellular, and contains no extraneous substances.
We descended the pumice hill with great rapidity almost at a run, and arrived at La Estancia in little more than two hours. We then mounted our mules, and following the track by which we had ​ascended the preceding day, we reached about four o'clock the country house of our hospitable friend Mr. Barry.
The difficulties of this enterprise have been much exaggerated, the ascent on foot is not a labour of more than four hours at most, and the whole undertaking not to be compared in point of fatigue to what the traveller undergoes who visits the Alps. That the ascent must be hazardous in a storm of hail and snow there can be no doubt, but to cross Salisbury plain may sometimes be dangerous. Yet stripped of poetical terrors and divested of the eloquent description of some writers, there is perhaps no mountain in Europe, the ascent of which does not furnish more difficulties than the Peak of Teneriffe.