Finally, the earlier is the warmer season with less danger to vulnerable feet and requiring a lighter equipment. CHAPTER XVII THE ROUTE TO THE SUMMIT The reader who has carefully followed the preceding story will hardly have failed to notice that the route which has been chosen as the only one offering reasonable chances of success remains still very largely a matter of speculation. But the reconnaissance, unless it were actually to reach the summit, was obliged to leave much unproved, and its value must depend upon observations in various sorts and not merely upon the practice of treading the snow and rocks. Speculation in this case is founded upon experience of certain phenomena and a study of the mountain's features; and it is by relating what has been only seen with known facts that inferences have been drawn. It may perhaps be accounted a misfortune that the party of 1921 did not approach Chang La by the East Rongbuk Glacier. The Lhakpa La proved a bigger obstacle than was expected. But in conditions such as we hope to find before the monsoon, this way would have much to recommend it. It avoids all laborious walking on a dry glacier, and with hard snow the walk up to the pass from the camp on stones at 20,000 feet should not be unduly fatiguing. Still the fact remains that the descent from the Lhakpa La on to the East Rongbuk Glacier is not less than 1,200 feet. Would it not be better to follow up this glacier from the Rongbuk Valley? The absence of wood on this side need not deter the party of 1922. For them plenty of time will be available sufficiently to provide their base with fuel, and the sole consideration should be the easiest line of approach; and though no one has traversed the whole length of the East Rongbuk Glacier, enough is known to choose this way with confidence. Here, as on other glaciers which we saw, the difficulties clearly lie below the limit of perpetual snow, and the greater part of them were avoided or solved by Major Wheeler, who found a practicable way on to the middle of the glacier at about 19,000 feet, and felt certain that the medial moraine ahead of him would serve for an ascent and be no more arduous than the moraines of the West Rongbuk Glacier had proved to be. The view of this way from the Lhakpa La confirmed his opinion, and though it may be called a speculation to choose it, whereas the way from the East has been established by experiment, it is a fair inference from experience to conclude that the untraversed section of the East Rongbuk Glacier, a distance which could be accomplished very easily in one march if all went well, will afford a simple approach to Chang La.