Views of this kind affect the imagination and impress themselves upon the memory more than most. Amongst the many wide vistas or actual panoramas which a mountain-climber of a few years' experience must have seen, he will doubtless freely admit that there are few which he can recall to his memory with any completeness. The first he ever saw overwhelmed him with their intricate elaboration. Later on, when he knew better what to look for, his susceptibility to impression was already lessened. The same is likely to be true of valley views. How many of them can we conjure up in any detail? The Matterhorn from Zermatt, Mont Blanc from Chamonix, and a few other similarly well-known prospects we know by heart; but of how many valley views, that we have only beheld once or during a short interval, can we form a visual image in our minds. My own experience leads me to conclude, though without making any allowance for a possibly large personal equation, that desert views are more memorable than those in which fertility predominates. Various views in the naked Indus valley are firmly fixed in my mind, though none of them were more than briefly beheld. The same is true of the scenery in the desert volcanic regions with which I am acquainted: the neighbourhood of Arequipa in Peru, parts of the provinces of Oruro and Potosi in Bolivia, the surroundings of the volcanoes of Ascotan in Chile, and of Aconcagua in the Argentine. In all these districts the scenery I beheld remains photographed in my memory with exceptional vividness, not merely its strangeness but its beauty, and the element in the scenery most vividly memorable is the element of colour.
In fact both colour and forms are strange to an eye accustomed to look upon the fertile and normally habitable regions of the earth. This is true not merely of the mountains themselves and their constituent parts but of all their surroundings. I have never looked down upon the boiling interior of an active volcano, such as travellers to Hawaii are privileged to behold on the top of Mauna Loa. That must be a sight passing wonderful. Nor have I ever beheld an erupting volcano from near at hand. But I have seen enough in the volcanic districts of South America to realise the marvels and fascinations they contain. Let me be forgiven for quoting one or two passages from my book on the Bolivian Andes, which were written when the impressions were fresh, though not a detail of them has yet escaped me.