find a ruined city, that the ruins and relies may be studied?"
"Here are the orders," spoke Tom, a bit sharply, not answering the question. "We'll camp and have supper, and then we'll go on and make all the distance we can after dark."
"What, travel at night?" cried the Mexican, as if in horror at the suggestion
"Yes; why not?" asked Tom calmly. "They can't see us after dark, and if we can strike off on another trail we may throw them off our track. Surely we'll travel after supper."
"But it will be night—dark—we never work after dark," protested Delazes.
"You're going to this time," declared Tom grimly.
"But the oxen—they are not used to it."
"Nothing like getting used to a thing," went on the young inventor. "They won't mind after a rest and a good feed. Besides, there is a moon to-night, and it will be plenty light enough. Tell the men, Senor Delazes."
"But they will protest. It is unheard of, and"
"Send them to me," said Tom quickly. "There'll be double pay for night work. Send them to me."
"Ah, that is good, Senor Swift. Double pay!
