Many people seem to think that it is one of the duties of an explorer to "rough it," and to "trust to luck" for his food. I had found on my first two expeditions, in Venezuela and Colombia and across South America, that the result of being obliged to subsist on irregular and haphazard rations was most unsatisfactory. While "roughing it" is far more enticing to the inexperienced and indiscreet explorer, I learned in Peru that the humdrum expedient of carefully preparing, months in advance, a comprehensive bill of fare sufficiently varied, wholesome, and well-balanced, is "the better part of valor," The truth is that providing an abundance of appetizing food adds very greatly to the effectiveness of a party. To be sure, it may mean trouble and expense for one's transportation department, and some of the younger men may feel that their reputations as explorers are likely to be damaged if it is known that strawberry jam, sweet chocolate and pickles are frequently found on their menu! Nevertheless, experience has shown that the results of "trusting to luck" and "living as the natives do" means not only loss of efficiency in the day's work, but also lessened powers of observation and diminished enthusiasm for the drudgery of scientific exploration. Exciting things are always easy to do, no matter how you are living, but frequently they produce less important results than tasks which depend upon daily drudgery; and daily drudgery depends upon a regular supply of wholesome food. We reached Arequipa, the proposed base for our campaign against Mt. Coropuna, in June, 1911. We learned that the Peruvian "winter" reaches its climax in July or August, and that it would be folly to try to climb Coropuna during the winter snowstorms. On the other hand, the "summer months," beginning with November, are cloudy and likely to add fog and mist to the difficulties of climbing a new mountain. Furthermore, June and July are the best months for exploration in the eastern slopes of the Andes in the upper Amazon Basin, the lands "behind the Ranges." Although the montaña, or jungle country, is rarely actually dry, there is less rain then than in the other months of the year; so we decided to go first to the Urubamba Valley. The story of our discoveries there, of identifying Uiticos, the capital of the last Incas, and of the finding of Machu Picchu will be found in later chapters. In September I returned to Arequipa and started the campaign against Coropuna by endeavoring to get adequate transportation facilities for crossing the desert.