experiment of Bouguer, to commence under the tropics, nearly at the height of Pinchincha, or 2430 toises above the level of the sea. By this nothing more is meant, than that the temperature of the air at this height, is, during some part of every day in the year, below the freezing point, and consequently that the snow here is permanent. It is obviously impossible to determine ac curately the precise height of this lower term of con gelation. It is liable to be affected by various circum stances, and must therefore be subject to considerable irregularities. When a mountain has a volcanic tendency, the heat excited by its internal commotions will have the effect of raising the term of congelation. A similar effect will be produced by the particular form and extent of the base ; while, on the other hand, if the mountain is considerably elevated, and presents a large surface of perpetual snow, the cold which is thereby diffused upon the surrounding regions, will have the tendency to bring it nearer to the surface of the earth. It is found, how ever, with regard to the mountains of Peru, that these opposing circumstances nearly destroy one another ; for so regular is the line which marks the lower boundary of the snow during the summer months, that it is pos sible, by merely tracing it with the eye, to form a pretty accurate estimate of the height of the moun tains.
As we descend from this line, or term of congelation, nothing is to be seen for the space of 100 or 150 toises, but naked rocks and barren sands. A little lower we begin to observe mosses fringing the rocks, and dif ferent kinds of heaths, and sometimes round hillocks, composed of a spongy kind of earth, on which are found stellated plants, the petals of which resemble the leaves of the yew tree. Below this, for the space of SOO toises, the ground is covered with a kind of thin grass, which rises to the height of a foot and a half, or two feet, and is called outchouc, in the language of the Incas. This grass or hay is the distinguishing feature of the Paramos. As we descend still farther, we first meet with small shrubs, and afterwards enter the woods, which become gradually thicker as we approach the plain, which con stitutes the habitable and cultivated part of the province of Quito. Such is the general appearance of the in terior sides of this double chain of mountains. It is obvious, however, that the different characters of the soil, its particular exposure, the winds, the seasons, and several other physical circumstances, will often cause the limits of the regions which we have now described to vary considerably.
In order to convey to our readers some practical idea of the height of these mountains, and of the remarkable severity of the weather on their summits, we shall relate some of the more interesting incidents which occurred to Bouguer and Condamine on the top of Pinchincha. The peculiar difficulties which they had to encounter on this elevated station, seem to have arisen chiefly from the violence of the winds, and the extreme severity of the cold. Hitherto they had been accustomed to pitch a number of field tents, for the accommodation of their party ; but here they were obliged to content themselves with a single hut, which was so small that they could hardly all creep into it. In this confined hovel, they had no other light than what was furnished by a few lamps, which they kept constantly burning, as much with the intention of producing heat, as of supplying light. Yet, notwithstanding the smallness of the place, and the heat of the lamps, so intense was the cold, that, while eating, each of them was obliged to keep his plate over a chafing dish of coals, to prevent his provisions from freezing. The effect of the cold upon the different parts of their bodies was not less !emarkable. Their feet were swelled, and so tender, that they could not bear the heat, while every attempt at walking was at tended with intolerable pain. Their hands were covered with chilblains, their lips were swelled and chopped, sd that it was impossible to move a muscle of their face, or even to speak without drawing blood. To prevent these
baneful effects of the cold, they sometimes attempted to raise the temperature of their bodies, by drinking strong liquors ; but this was soon found to be a useless expedient, and no better preservative than common water.
In consequence of this extreme degree of cold, they were compelled, during the greater part of their stay on this elevated station, to keep within the hut ; a pre caution which was rendered still more necessary by the violence of the winds, and the thickness of the fog, which sometimes involved them in midnight darkness. This mist was occasionally seen rolling down the sides of the mountain, uncovering its summit, and presenting the craggy rock, on which our travellers were seated, like a desolate island in the midst of a tempestuous ocean. The scene now became truly magnificent, and peculiarly interesting. They heard the noise of the tempests dis charging themselves on Quito, and the neighbouring country. They saw the lightnings darting through the dark clouds, and were at every instant startled by the loud peals of thunder which rolled beneath them. Meantime all was peace and serenity in the immediate neighbourhood of their solitary hut. The wind was abated, and the sky clear ; and even a kind of cheerful ness and warmth was diffused around this bleak and dreary mansion by the enlivening rays of the sun. But this condition of things was seldom of long continuance. The fogs again returned, which, in that elevated situa tion, added considerably to the difficulty of breathing. Snow and hail fell incessantly, and the wind resumed its former violence, so that they seemed subjected to the dreadful alternative of being driven with their hut down the precipice, or buried under it, by the rapid ac cumulation of the ice and snow. It is difficult to con ceive the extreme violence of the wind in these elevated regions. Its velocity, which was indicated by the rapid motion of the fog, was calculated to excite considerable alarm, and was often so great as even to dazzle their sight. Nor were the horrid concussions heard in the interval of the blast, occasioned by the fall of enormous fragments of rocks, match adapted to allay their fears. Against this fury of the blast, they employed every precaution which their situation could supply, by fast ening the door of their hut with thongs of leather, stop ping the chinks in the inside, and covering the whole, with straw ; but all these devices were found insufficient to protect them from the storm. In addition to these sources of uneasiness, arising from the rage of the elements, and the asperity of the climate, they were ex posed to great danger from another quarter. In con sequence of the great accu.amlation of snow during the night, and the door of their hut being fastened on the outside, it became necessary that some persons should lodge without the hut, whose business it was to attend in the morning, to untie the thongs, and remove the snow which every night blockaded the door. This task was allotted to a few Indians, who, though lodged at a more comfortable station, in the lower part of the mountain, soon began to complain of the severity of the weather, and the fatigue of the journey, and were thereby led to form the resolutiontf deserting their employers. This resolution, which was immediately carried into effect, would undoubtedly have proved fatal to the whole com pany, had not one of the Indians, more faithful than the rest, escaped from his companions, and performed him self, with much difficulty, the usual task of them all. Such were some of the hardships to which the French mathematicians were subjected during their abode at Pinchincha, from which our readers will be enabled to form some idea of the greater difficulties which the traveller must encounter, in ascending the loftier sum mits of Catopaxi, Chimborazo, &c.