Don Luis talked with the enthusiasm of one who understood and loved mules.
Then, finally, they passed to the office.
"Now, I shall be glad to talk with you for hours," the Mexican hidalgo assured the young engineers.
Dr.Tisco, as though to show that he took no personal interest in the talk, retired to an armchair at the further end of the room.
Nevertheless, the secretary observed carefully all that was said.
Covertly he studied the faces of the young engineers at all times.
"Ask me what you will," begged Don Luis, as he sank into an easy chair close to the table on which Tom began to arrange his envelopes of specimens taken from the mine.
"First of all, Don Luis," Tom began, "you spoke of some problems that you wished us to solve in the operation of your mine." "Yes, Senor Tomaso." "I would like to ask you what the problems are that we are to consider," Tom announced.
"Did you not see some of the problems before you, while we were going through the mine ?" inquired Montez.
"At the risk, Don Luis, of appearing stupid, I must confess that I did not." "Ah, well, then we shall come to the problems presently.

You have other questions.

Ask some of them." For a moment or two Reade studied what he had written on the various envelopes before him.

Then he picked out two.
"Here, Don Luis," the young chief engineer went on, "are samples of two lots of ore.

The first is from the pile that we found pried loose when we went into the first tunnel that we visited.