JOURNEY

TO THE

SUMMIT OF MONT PERDU,

THE

HIGHEST MOUNTAIN OF THE PYRENEES.

BY L. RAMOND,

Member of the National Institute; and read in that Society the 19 Floreal, an. 11.

I HAD convinced myself, by various attempts to reach the summit of Mont Perdu, that it was only by its eastern side that it could be accomplished; and I was persuaded that even its peak might be ascended by the way of the defile of Fanlo, unless any insurmountable obstacle lay concealed from me, in the space which separates the peak from the defile.

It was therefore towards this doubtful intervening space that all my attention and thoughts were directed, and I had more than once or twice urged my guides to explore it; two of whom at length, last summer, determined to gratify me, and I marked their route for them; but having reached the foot of the mountain, they thought proper to go from my instructions, and to trust to the guidance of a Spanish shepherd, less acquainted than themselves with Mont Perdu; and they had nearly paid very dear for so doing. This journey was indeed perilous, being obliged to pass a night (so ill had they contrived for themselves) beneath the glacier of the peak, without shelter, without fire, and almost without food. The second day, however, they conquered the last difficulties, and reached the summit, but so worn out, that they had scarcely ability to explore it; and so confusedly did the man who came to me with the tidings of their success describe the places, that I was more than once, in the course of his narrative, apprehensive they had totally failed in their object: one circumstance was evident enough, which was, that the path they took was not the proper one.

Be this as it may, I instantly determined upon my departure, resolving to follow scrupulously the way I had by my eye traced out to myself, by which I did not doubt I should steer clear of those dangers to which my guides had been exposed; nor was I disappointed: I had conceived the true route, and found myself upon the summit of Mont Perdu, less exhausted by the labour of the journey than I was by exploring its base. I took my departure from Barege the 9th of August 1802, and having gained the valley of Gidre and Estaube, I took my station on the height of Port Penide, the exact elevation of which it was very desirable to ascertain, and by the observation of the barometer I found it to be one thousand two hundred and ninety-one toises; but the Port du Penide is by no means the highest or most difficult passage of this portion of the Pyrenees.

This calculation afforded me the opportunity of ascertaining with precision the extent of the lesser chain of permanent snows, which terminated at the absolute elevation of one thousand two hundred and fifty toises.

I had a good spirit-level, which furnished me also with a very interesting result: I proved by it that the defile of Pimeni, from which I was separated by the valley of Estaube, was precisely of the same elevation with the Port du Penide, and likewise with the defile of Fanlo, divided from me by the valley of Beouse. This conformity of elevation between three corresponding and alike disposed points, is a discovery by no means immaterial to a geological history of Mont Penide.

But in vain was our ascent to the defile of Fanlo: it was indispensable we should retrograde; we were to descend considerably ere we could re-ascend. We directed ourselves obliquely towards the enormous walls which bear up the lake of Mont Perdu and its terrace, which brought us to the point from whence the torrent precipitates itself, in a frightful cataract, to the bottom of the valley of Beouse.

Here we found ourselves upon a small well turfed, but very inclining platform; and here too we met with a flock of sheep under the guidance of a shepherd, a species of savage, unable to understand us even in his native language. Mont Perdu was suspended over his head, yet was he as little acquainted with it as if it had constituted a part of the Andes. He had, however, a knowledge of the defile of Fanlo, here designed under the name of Niscle, and he engaged to conduct us to it the next day. We, in conse. quence, passed the night with him in the open air, amidst the vapour of the cataracts, and the angry portents of a threatening tempest on every side. I took the height of this station, and found the mean between two observations to be one thousand and three toises.

Our first labour in the morning was to cross the torrent which discharges itself from the lake; its depth, its rapidity, and particularly the coldness of the water, rendered this effort of some difficulty. The water caused a rise of two degrees only in the thermo. meter above the freezing point.

From this place until we reached the summit of the defile of Niscle, we experienced no other difficulty than what was occasioned by the extreme inclining of the slopes. I ascertained the height of the defile to be exactly upon a level with that of the Penide, as it is also with the border of the terrace near the lake of Mont Perdu; the lake itself is somewhat higher. I found, on trial, its absolute elevation to be something more than thirteen hundred toises. Here then we have four excavations of equal form and height, viz. the valley of the lake, the defile of Niscle, and those of Pimene and Penide; which I consider as the remains of an ancient valley, hollowed by the currents, after the destruction of the beds of Mont Perdu, and possibly before their emersion; a valley which afterwards may have been transversely cut by the great rents which now actually form the vallies of Beouse, d'Estaube, and Gavarmi. Hitherto I had proceeded upon assured grounds; I have already described what is singular upon this secondary soil, composed of irregular beds thrown up by the accidents of nature, the receptacles alternately of

marbles, breccia, limestone: some compact, and mingled with flint; others gross, and more or less mixed with clay and sand, and all sprinkled with zoophytes and testaceous fragments. I now found myself upon the continuations which constitute the summits of Mont Perdu, the soil of which, it was evident to me, had never changed either its position or nature. I had never before been in a situation so convenient, correctly to notice its structure. The side of the mountain which presented itself to me, that commands the defile to the east, arose to a perfect peak, so that the view I had of it was completely transversal, and perfectly characteristic of the position of the beds which formed the ridges of the mountain I was about to climb.

The whole of these beds, allowance being made for their windings, incline generally so much to the north, that the greatest part of them hardly vary from a vertical situation, and have a direction very visibly parallel with the general direction of the chain; a circumstance not otherwise to be explained or accounted for than from some violent convulsion of nature; and it is not to be doubted that this irruption has taken place under the very waters, which have removed these beds, for their upper trenches are covered with thick layers of shelly free-stone, inclining rather to the northern horizon, and which differs in nothing besides from the free-stone found in the beds.

What I had the opportunity of seeing upon the mountain of Niscle, I was about once more to explore on the summit of Mont Perdu, but in portions, and in detail, surrounded by the snows and ice, and embosomed midst the disorder and ruins of nature, where it is hardly possible to discern the order and structure of these irregular interwoven shelves.

The first stages to the ascent of Mont Perdu present themselves to us to the west of the defile of Niscle, and they present themselves with an abruptness and grandeur which announce the avenues to its summit. Four or five terraces piled one upon another form as many flights of steps, covered in part either with snow or fragments, which tend not a little to facilitate the access to these otherwise inaccessible walls. The first of these fragments are blocks of more than ordinary size, and apparently belong to the chain of the parasite bed of free-stone which copes the mountain of Niscle. It must be noticed, I apply the name of free-stone to those gravelly calces, of which sand constitutes the most apparent part. Testaceous fragments are found in those free-stones; and with them fragments of a calcareous schistus, strongly polluted with clay, and spread over with a small extended polypus, moderately compressed, sometimes ramified, its surface pierced with simple pores, but remarkable for a small projecting belt which surrounds them.

I very shortly passed beyond these blocks, and continued my route, ascending obliquely from the north-east to the south-west, that is to say, in a direction which cut nearly in a right angle the general direction of the ridges, and soon reached the ruins which belong to the continuation of the beds of which even the mass or body of the mountain of Niscle is formed. Here I recognized the compact stone of Marbore, black or gray within, but soon whitening when exposed to the air, and spreading itself in a spontaneous manner in small irregularly angled fragments. It is most generally fetid, but in no region did I experience it so much so as in this; the very treading it was sufficient to infect the air with an insuperable smell and a nausea, bearing no possible relation to that caused by percussion in the common hepatic and bituminous stones.

It took us near an hour to cross these fragments, or rather these wrecks, and we were much overpowered in this part of our journey by the efforts required as well to climb the excessive slanting declivities, as to struggle incessantly against the loose earth, tending invariably to the precipice. At length we found ourselves upon the upper terrace, and on a range of rocks, which at the first forms a narrow ridge, but widens by degrees, and becoming safer, brings us to a sort of valley where the ices begin which encircle the peak.

In the bare and uncovered part of this extended ridge I noticed some large pieces of a compact calcareous blackish stone, crowded with great lumps of silex of the same colour; they slightly inclined from the vertical to the south, and follow the same direction with the ridge and chain. It is a repetition of beds of the same nature I have noticed in the Port de Penide, Pimene, and elsewhere. Here, as there, they appear to be of the number of those whose direction is most evident. They were distinguishable by me on the mountain of Niscle, yet in my view, where this intrenchment widens itself from the base to the summit of its westerly side. The kidneys of silex are of larger volume there than at Ports de Penide, and are at the same time exceedingly irregular; though I found one figured like an hexadrical oblique prism, which singular specimen I have de. posited in Mr. Hauy's collection; had I met with it in the very heart of the rock, I should have been tempted to examine the direct work of crystallization, but it was of the number of those fragments spread over the surface of this ground; and as all the kidneys with which these stones abound, are shattered in every sense by straight planes, the natural effect of retiring waters I am warranted in the conjecture, that this prism is a detached portion of a more considerable kidney, in which the fissures had accidentally met under the angles, which quartz particles have an incessant tendency to form.

At Port Penide there are many shells contained in this stone; here I did not perceive any, but it is probable some may be found; besides, I have met with layers of a calcareous stone in these beds, very argillaceous, and much mixed with sand, which contained so large a quantity of nummularia, as gave it an appearance of having been almost entirely composed of them. These beds soon slip under the ices, and become no longer visible. We now approached the borders of these glaciers, which have here their origin, and consequently but of very gentle declivity. Nevertheless, we found the crossing of them disagreeable enough; sometimes we found the surface hard and slippery, at others we sunk up to the knees in the recent snows, fallen upon the summits in the month of June. Beneath this snow too, in our treadings, we were sensible of rents, in which we ran the risk every instant, of being lost. The exposed clefts also intercepted our passage, and we had nearly been altogether stopped, at two hundred metres* below the summit, by one of them, which extended transversely from the origin of the glacier, to the steep of the valley of Beousse. It was but three days before, that my guides had commodiously passed this cleft, by a bridge of snow, which was now dissolved; and which it was now our business to effectuate by leaping, which we succeeded in, and thereby conquered the last obstacle. I measured the depth of the cleft, and found it forty feet; and as the place where we crossed, corresponded with the convexity of the mountain; it must evidently have been the place where the ice was of the least thickness.

From thence I beheld the summit which had hitherto been constantly concealed from me, by the position of the declivities over which I had passed. It presented itself in the form of an obtuse cone, clothed in spotless, resplendent snow; the sun shone with uncommon pureness and brilliancy; but its disk was shorn of its rays, and the sky appeared of a deep blue, and so strongly shaded with green, that even the guides were struck with the strangeness of its aspect. The first tint has been observed on all the high mountains; but there is no example of the second, and I am myself totally ignorant, to what this singular optical illusion may be attributed.

At a quarter past eleven, I reached the summit, and, at length, had the gratification of contemplating, at my feet, the whole of the Pyrenees, and instantly set to work with my instruments. The wind blew very boisterous from the W. S. W.; which threw difficulty in the way of my operation. I marked the state of both the barometer and the thermometer at noon. M. Dangos made a correspondent observation at Tarbes, with the instruments he took with him to Mount Etna; which have been carefully compared with mine. My barometer placed upon the crest of the cap of snow, after due correction, stood at 18i. 11.141.; at Tarbes it was found at the same time, to stand at 27i. 1.471. The difference of logarithms then give one thousand five hundred and fifty toises, for the vertical height of the measured column. On the other hand, the thermometer at Tarbes stood at 20° 5'; by Reamur's scale, and at the summit of the peak, at 5° 5' by the same scale; which leaves to be added, agreeably to Mr. Trembley's formula, 12.11 toises, and determines the height of the column to be 1562.11 toises: Now Vidal's trigonometrical operations fix the elevation of Mont Perdu at one thousand five hundred and ninety-nine toises beyond that of Tarbes; which makes a difference of at least 37 toises, or 3 of the measured column. Mr. Laplace's formula augments this difference, more than double; and so does Mr. Deluc's, but Schuckburgh's correction of the latter brings the result very exact to the formula of the former.

It is my intention to examine more carefully this observation, when I give an account of the whole of my barometrical observations; at present I shall content myself with observing that the wind was exceedingly tempestuous, and blew from the southern region; and the sky around me very portentous of storm; and that all my observations, made under similar circumstances, have ever been short of the heights of the places I would measure. I shall further observe that the correction of temperature, which has already been so often hazarded, must not here be confided in. Local circumstances, infinitely varied, most certainly variously influenced every part of the same column of air it was permitted me to examine. In effect, if the thermometer, placed by the side of the barometer, on the lap of snow, and at four feet above the surface, announced 5° 5' of heat, the same thermometer brought down to the surface of the snow fell to 2o, by reason of the absorbent nature of the heat, which occasioned a rapid evaporation of the surface. At the same time another thermometer, placed likewise in the shade, at four feet from the surface, but upon the southern face of the peak, which the snows had left, indicated +10°, and this same thermometer, placed on a level with the surface, and exposed to the sun, rose to +18.25. Finally, I must remark, and that too as a very singular and fortunate circumstance, that Mont Perdu, and the Defile of the Giant (Col du Geant) where Saussure made such a series of valuable observations, we found to be precisely of the same height, since the trigonometrical observations give to each one thousand seven hundred and sixty-three toises, of actual elevation; for the mercury retained its situation at the same point in both these elevated spots; and besides the barometrical calculation of heights furnished results to Mr. Saussure so far below his geometrical proofs, that this illustrious naturalist has judged it proper to relinquish them altogether, notwithstanding they were grounded upon eighty-five observations, made within the course of fifteen days.

The peak is covered with snow from the great glacier to the summit, but the thickness of the snow gradually diminishes, and becomes very inconsiderable towards the top,