"Bluff," replied his uncle. "I'll tackle Don Ramon Diaz, tell him I'm badly in need of a holiday. Fact!" he continued; "haven't been ten miles from El Toro for months. We'll get his permission for a ten-days shooting trip up the Rio Guaya. He'll probably take good care that we do go up, not down, because he'd never imagine that we were fools enough to attempt to penetrate that wild and mountainous country. We'll give out that we are exploring the Rio Tinto, but in reality we'll make a dash up the Rio del Morte as far as we can by water and foot it the rest of the way. It won't be a picnic, Peter, I can assure you. We'll have to travel light, depend upon our rifles for food, probably be half frozen before those mountains are crossed--but it's worth it." "Rather!" agreed Peter Corbold enthusiastically. CHAPTER XI Up the Rio Guaya "How does your marvellous searchlight progress, Señor Strong?" inquired Don Ramon Diaz. Brian shook his head. "Not at all well, Señor," he replied. "In fact, I'm beginning to think I've worked myself to a standstill." "Is that so?" said the Rioguayan, giving the Englishman a sharp glance. "But, as a rule, one does not test searchlights by day." "In this case one does," replied Brian. "If the combined telephone and searchlight apparatus can be perfected--as no doubt some day it will--you will reap the benefit. Or at least, the Republic of Rioguay will. Regarding daylight experiments, you will agree that it is easier to make delicate adjustments by natural light. The testing under actual working conditions at night will be made later. But that brings me to another point, Señor. I'm badly in want of a holiday." "Not a long one, I beg?" "Oh no," replied Brian jauntily. "A week or ten days. My nephew and I would like to have a shooting trip up the Rio Tinto." "It is dangerous--very dangerous," declared Ramon Diaz. "And, Señor, we do not want to lose your valuable services just yet." "Perhaps not," rejoined the Englishman. "But there are other ways of doing that without running risks on the Rio Tinto." "What do you mean?" demanded the Rioguayan suspiciously. "For instance, I might have brain fever through overwork," replied Brian. "I feel pretty confident that on my return I can tackle the present perplexing problem with a far better chance of success."