He put the question to Charley Moi, and when the smiling-faced Chinaman replied, Frank caught his breath.
"That easy, bloss," said Charley, nodding. "Happen this way. Long time black me 'gage with sahib, like one know out in Canton. Think have samee big joss some bit up here in canlon. Me to bling grub to certain place evly two month. Him give me list what buy, and put cash in hand. Know can trust Chinaman ebery time. Many time now me do this; so know how make trail up-river, much far past same tourist use. Sabe, Flank, Blob?"
The two boys stared at each other, unable to say a word at first. It was as if the same tremendous thought had come to each.
"Gee whiz! did you get on to that, Frank?" finally ejaculated Bob.
"I sure did," replied his chum, allowing his pent-up breath full play.
"Charley says he engaged himself to a gentleman long ago; perhaps it was as much as three years back, the time that the professor disappeared from the haunts of men. And, Frank, his part of the contract was to come to a certain point away up here in the Grand Canyon, once every two months, at a time agreed on, bringing a load of food, as per the list given him by this mysterious party."
"It must be Professor Oswald!" exclaimed Frank. "I've been wondering all the time how under the sun he could have supplied himself with food these long months if he'd cut loose from the world, as he said in that note he had. Now the puzzle begins to show an answer. Charley Moi is the missing link. He has kept the professor in grub all the time. Did you ever hear of such luck? First we run across that old Moqui, who has been in touch with the man we want to find; and now here's the one who comes up here every little while to deliver his goods, and get a new list, as well as money to pay for the same. It's just the limit, that's what!"
He turned to the Chinaman, and continued:
"Did you happen to notice, Charley, whether this party you are working for is a bald-headed man? Has he a shining top when he takes his hat off; and does he bend over, as if he might be hunting for diamonds all the time?"
The Chinese guide smirked, and bobbed his head in the affirmative.