times the peak was entirely hidden from their eyes by the fog, at other times it broke upon them in terrific proximity; and, like an enormous pyramid, threw its shadow over the clouds rolling beneath their feet.

About three in the morning, by the sombrous light of a few fir torches, they started on their journey to the summit of the Sugar-loaf. They scaled the volcano on the northeast side, where the declivities were extremely steep; and after two hours' toil reached a small plain, which, on account of its elevated position, bore the name of Alta Vista. This was the station of the neveros, those natives whose occupation it was to collect ice and snow, which they sold in the neighbouring towns. Their mules, better practised in climbing mountains than those hired. by travellers, reach Alta Vista, and the neveros are obliged to transport the snow to that place on their backs. Above this point commenced the Malpays, a term by which is designated here, as well as in every other country subject to volcanoes, a ground destitute of vegetable mould, and covered with fragments of lava.

Day was beginning to dawn when the travellers left the ice-cavern. They observed, during the twilight, a phenomenon which is not unusual on high mountains, but which the position of the volcano they were scaling rendered very striking. A layer of white and fleecy clouds concealed from them the sight of the ocean, and the lower region of the island. This layer did not ap pear above five thousand feet high; the clouds were so uniformly spread, and kept so perfect a level, that they wore the appearance of a vast plain covered with snow. The colossal pyramid of the peak, the volcanic summits of Lancerota, of Forteventura, and the isle of Palma,

46

A GRAND ILLUMINATION.

were like rocks amidst this vast sea of vapours, and their black tints were in fine contrast with the whiteness of the clouds.

While they were climbing over the broken lavas of the Malpays, they perceived a very curious optical phenomenon, which lasted some minutes. They thought they saw on the east side small rockets thrown into the air. Luminous points, about seven or eight degrees above the horizon, appeared first to move in a vertical direction; but their motion was gradually changed into a horizontal oscillation. Their fellow-travellers, their guides even, were astonished at this phenomenon, without either Humboldt or Bonpland having made any remark on it to them. The travellers thought, at first sight, that these luminous points, which floated in the air, indicated some new eruption of the great volcano of Lancerota; for they recollected that Bouguer and La Condamine, in scaling the volcano of Pichincha, were witnesses of the eruption of Cotopaxi. But the illusion soon ceased, and they found that the luminous points were the images of several stars magnified by the vapours. These images remained motionless at intervals, they then seemed to rise perpendicularly, descended sideways, and returned to the point whence they had departed. This motion lasted one or two seconds. Though they had no exact means of measuring the extent of the lateral shifting, they did not the less distinctly observe the path of the luminous point. It did not appear double from an effect of mirage, and left no trace of light behind. Bringing, with the telescope of a small sextant, the stars into contact with the lofty summit of a mountain in Lancerota, Humboldt observed that the oscillation was

ACROSS THE MALPAYS.

47

constantly directed towards the same point, which was towards that part of the horizon where the disk of the sun was to appear; and that making allowance for the motion of the star in its declination, the image returned always to the same place. These appearances of lateral refraction ceased long before daylight rendered the stars quite invisible.

The road, which they were obliged to clear for themselves across the Malpays, was extremely fatiguing. The ascent was steep, and the blocks of lava rolled from beneath their feet. At the peak the lava, broken into sharp pieces, left hollows, in which they risked falling up to their waists. Unfortunately the listlessness of their guides contributed to increase the difficulty of this ascent. Models of the phlegmatic, they had wished to persuade Humboldt and Bonpland on the preceding evening not to go beyond the station of the rocks. Every ten minutes they sat down to rest themselves, and when unobserved they threw away the specimens of obsidian and pumice-stone, which the geologists had carefully collected. They discovered at length that none of the guides had ever visited the summit of the volcano.

After three hours' walking, they reached, at the extremity of the Malpays, a small plain, called La Rambleta, from the centre of which the Sugar-loaf took its rise. They had yet to scale the steepest part of the mountain, the Sugar-loaf, which formed the summit. The slope of this small cone, covered with volcanic ashes, and fragments of pumice-stone, was so steep, that it would have been almost impossible to reach the top, had they not ascended by an old current of lava, the débris of which had resisted the ravages of time. These

48

SUMMIT OF THE SUGAR-LOAF.

débris formed a wall of scorious rock, which stretched into the midst of the loose ashes. They ascended the Sugar-loaf by grasping the half-decomposed scoriæ, which often broke in their hands. They employed nearly half an hour to scale a hill, the perpendicular height of which was scarcely five hundred and forty feet.

When they gained the summit of the Sugar-loaf they were surprised to find scarcely room enough to seat themselves conveniently. They were stopped by a small circular wall of porphyritic lava, with a base of pitchstone, which concealed from them the view of the crater. The west wind blew with such violence that they could scarcely stand. It was eight in the morning, and they suffered severely from the cold, though the thermometer kept a little above freezing point.

The wall which surrounded the crater like a parapet, was so high, that it would have been impossible to reach the crater itself, if, on the eastern side, there had not been a breach, which seemed to have been the effect of a flowing of very old lava. They descended through this breach toward the bottom of the funnel, the figure of which was elliptic. The greatest breadth of the mouth appeared to them to be three hundred feet, the smallest two hundred feet.

The external edges of the crater were almost perpendicular. They descended to the bottom of the crater on a train of broken lava, from the eastern breach of the inclosure. The heat was perceptible only in a few crevices, which gave vent to aqueous vapours with a peculiar buzzing noise. Some of these funnels or crevices were on the outside of the inclosure, on the external brink of the parapet that surrounded the crater. Hum

EDGE OF THE CRATER.

49

boldt plunged the thermometer into them, and saw it rise rapidly to 154 and 167°. He also sketched on the spot a view of the interior edge of the crater as it presented itself in the descent by the eastern track.

The top of the circular wall exhibited those curious ramifications which are found in coke. The northern edge was most elevated. Towards the south-west the enclosure was considerably sunk, and an enormous mass of scorious lava seemed glued to the extremity of the brink. The rock was perforated on the west, and a large opening gave a view of the horizon of the sea.

Seated on the brink of the crater, Humboldt dug a hole some inches deep, into which he placed the thermometer, which rapidly rose to 107°. Some sulphurous crystals which he gathered here, consumed the paper in which he wrapt them, and a part of his mineralogical journal besides.

From the outer edge of the crater the admiring travellers turned their eyes towards the north-east, where the coasts were studded with villages and hamlets. At their feet were masses of vapour constantly drifted by the winds. A uniform stratum of clouds had been pierced in several places by the effect of the small currents of air, which the earth, heated by the sun, began to send towards them. The port of Orotava, its vessels at anchor, the gardens and the vineyards encircling the town, showed themselves through an opening which seemed to enlarge every instant. From the summit of these solitary regions their eyes wandered over an inhabited world. They enjoyed the striking contrast between the bare sides of the peak, its steep declivities covered with scoria, its elevated plains destitute of vege