what the point of view, this is what they say. We never got any man to point out a peak, and say, "That is Aconcagua."

The greatest drawback, however, to the climber and explorer in these regions is the terribly uncertain weather. M. Elisée Reclus speaks most truly of the mountain when he says:

Being surrounded by numerous rugged spurs, and everywhere furrowed by winding gorges, Aconcagua is of difficult access, although its upper section for a total height of about 6500 feet rises in a superb cone above the elevated pediment of the surrounding uplands. A broad snowfield, intersected by crevasses, is developed round the west and north-west slopes, but presents no great obstacle to the climber, nor would the higher and almost snowless escarpments be difficult to scale, but for the rarefied atmosphere and sudden snowstorms." In the summer months a terrible wind springs up soon after sunrise and usually blows the whole day. This wind renders all work of exploration difficult, and on the higher slopes, very dangerous. During the winter there is a deep snowfall, when the valleys are filled with snow, the drifts in places being of huge depth. When the spring sun clears this snow away, there is as a rule no more rainfall or snowfall till the next winter. The valleys are then like deserts, and the only place in which vegetation can be found is close beside some spring or stream, though even here the strong mineral quality of the water often destroys such vegetation. The result of this is, of course, a dust which is almost unendurable. Surveying in the upper valleys I have frequently been forced to wait for an hour before I could get a sight of a pole a thousand feet away, owing to tornadoes and eddies of dust. This dust penetrates everywhere-into food, into clothes, among books and papers, on the verniers of instruments, cutting and scratching them; in short, making life miserable and work almost impossible. During the day the sun has great power, and I have known the thermometers to mark nearly 90° in the shade. We suffered severely from the absence of trees or shelter under which to pitch a tent. We had to live in the open, and the fierce rays of the sun

beating down upon the canvas sides of our tent made the interior almost uninhabitable. Many a day have I spent, working out calculations, unable to go outside on account of the blinding dust-storm, while in the tent itself the heat was 110°. I cannot conceive of more miserable surroundings. We had to contend against temperatures and conditions that ranged between a Sudan campaign and an Arctic expedition. This, as I have said before, is perhaps the greatest difficulty in this country, for after some months' work, one's strength is exhausted, and there is no place to which to retire for a few day's rest under normal conditions. Storms spring up too with terrible rapidity. On the heights-that is to say above 16,000 or 17,000 feet-they often become veritable blizzards, though at a lower level they are as a rule only great gales of wind, with an occasional shower or flurry of snow. Lower down the ranges, between the Uspallata Valley and Mendoza, severe thunderstorms and cloud-bursts rage during the months of January and February. The lightning is especially vivid and dangerous. But these storms seldom extend to the higher Andes; upon two occasions only have I seen lightning at all near, though on a long summer evening, one can observe the bright flashes far over the ranges and pampas of Argentina. The prevalent wind during the summer is from the north-west, but I am told that this varies considerably from season to season. During our stay in these valleys the wind was particularly aggressive; in the following year there was scarcely any.

With irrigation the soil produces luxuriant crops. The proprietor of the posada at Vacas had a large field artificially irrigated by canals, where the grass grew with extraordinary abundance. On the Chilian side there is more vegetation in the valleys, and on going down some distance, large quantities of cacti are seen, and even small trees, though at no place in the valleys is there anything like the forests that are found farther south in old Patagonia.

Till last year there was some doubt as to which was the highest mountain of South America, but since Sir Martin Conway's triangulation of Illimani and Sorata or Illampu, it is

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admitted beyond question that Aconcagua overtops every other mountain there, and indeed every mountain outside the great ranges of Asia. There are still unmeasured mountains in Africa, such as the ranges of Ruwenzori, which are, I believe, estimated to be between 16,000 and 17,000 feet high. These, however, were measured from a great distance, and nobody knows what lies behind them. The expedition just starting for those regions will doubtless clear up the doubt, and settle these heights exactly. Tupungato rises above Chimborazo, Sorata, Illimani, and Sajama; it is still doubtful as to whether it exceeds the height of Mercedario. If Pissis' height of the Mercedario, viz. 22,315 feet, is correct, this would be the second highest peak in America. In any case it is now certain that Aconcagua, Mercedario, and Tupungato are the three highest mountains of the American

continent.

A

CHAPTER IV

UP THE VACAS VALLEY

FTER this historical and topographical excursion I return to our own story.

We were on foot at four o'clock on the morning of 9th December, Zurbriggen and I preparing for the trip up the Vacas Valley, of which I have already spoken. Our arriero and the mules we had hired at Vacas were late, as in these early days we did not know that it was useless to give an order to a native. The only way to get him to do anything is to send someone to make him do it about an hour before it has to be done. We intended to be up this valley only a few days, so we took a very small quantity of provisions, and told the arriero that he must supply himself with what he wanted. At about 5.30 we started, but we had not gone far before we suddenly remembered that we had not brought our binoculars with us, and so had to turn back for them. It is not until after several weeks of work that one gets into the way of remembering the hundred-and-one trifles necessary in an unknown country, even on a short journey. One can make oneself absolutely miserable for several days, for instance, by starting without, say, matches. One has to remember first and foremost what scientific instruments are required; secondly, note-books and pencils; thirdly, foods; then clothing and covering; besides which one must always be provided with extra pieces of string, straps, knives, etc. etc. To be fitted for this sort of work everyone must be a jack-of-all-trades, carrying a small but varied equipment for all purposes and all needs of repair. One must be ready at any moment to shoe a horse, mend a strap, or sew a patch on a coat; to estimate the distance between two points; to take