ete, pointing.

"And over across there is father, I guess," said Jack. "I hope he
found everything at the Esmeralda all right."

"Sure he did," said Pete confidently. "I tell you, these greaser
uprisings don't amount to a busted gourd. Mister Diaz's tin soldiers
come along, and 'pop-bang! Adios!' It's all over."

"But I have heard that in this case the insurrectionists of Northern
Chihuahua are exceptionally well provided with arms and ammunition,"
objected the professor. "The American government can't make out from
whence they are supplied with guns and munitions of war."

"Huh, where'd they git 'em from, I'd like to know?" snorted Pete. "The
border is well guarded at any point where they would be likely to ship
'em across, and----"

"How about the _unlikely_ points?" inquired the professor amiably.

"Um--ah--well," began Pete, somewhat stumped by this last, "I don't see
what that's got to do with it."

"But I do. Mexicans, my friend, are, as you should know, a cunning
race. Moreover, those of them who dwell along it know the border far
better than any white could ever hope to. By the admission of our own
secret agents, it has hitherto been impossible to find how the arms,
which the Chihuahua rebels are receiving, can reach them. It is
obvious, however, that there must be some way in which they do,
hence----"

"Waal, perfusser, hev it your own way," grunted Pete, rather red and
angry. The professor's logic did indeed seem unassailable. The rebels
of Northern Chihuahua were getting arms--but how? The cow-puncher and
the boys recalled now a visit made to Mr. Merrill's ranch some weeks
before by a party of United States secret agents.

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 wit