The men were puzzled and angry over their failure to locate the "leak." Somehow arms were being shipped across the border into Chihuahua from American soil, but just how had hitherto baffled all the efforts of their ingenuity to discover.
"There, there, don't be so easily offended," counseled the professor, perceiving Pete's palpable irritation. "After all, the matter has nothing to do with us. We are here to measure the mesa for scientific purposes, not to get into arguments over how a band of insurrectos are getting their arms. Come, boys, to work. Let us begin at the top, by measuring the altar. Suppose, Jack, you lay the tape on it, while I make a rough field sketch of the structure."
The boys, now over their first repulsion to having anything to do with the altar, about which such grisly memories clustered, eagerly began to carry out these orders, while Coyote Pete seated himself on the side of the summit overlooking the travelers' camp below, and amused himself by throwing small bits of detached rock down at the unoffending One Spot, Two Spot and Three Spot.
The base of the altar being duly measured and recorded, Jack, tape in hand, followed by the others, clambered up its rough sides, which afforded an easy foothold, for the purpose of ascertaining the dimensions of the top. To the lad's astonishment, however, there was no summit. That is to say, the altar was hollow.
The professor exhibited considerable scientific excitement on hearing this. The man of science had been greatly puzzled over the total absence of any traces of the human sacrifices he knew must have taken place there. He now hailed Jack eagerly.
"Are there not some bones or traces of sacrifices inside it, my boy?" he inquired excitedly.
"Nary a bone," shouted Walter cheerfully.
"Hold on, though," cried Jack. "There are some queer-looking things down in one corner."
Lowering himself inside the altar, he made for one corner of the erection, in which he had spied a heap of fragile-looking bones of some kind.
"Skeletons of snakes!" he cried, holding up one of these for the inspection of the professor, who had by this time hoisted his bony frame over the top of the altar and now stood beside them.