The map of South America shows Peru as a rather long, narrow country, broadening at the north, and presumably tropical in climate judging by its position just south of the Equator, but with high mountains close to the coast. But it does not show the cold ocean current coming from the south—the Humboldt Current—or ar least we are not accustomed to noticing such presumably minor features, even though in the case of Peru, this is equal in importance with the mountains in determining the climate of the country and every factor that the climate may affect.