One could not help becoming infected by Whitney’s enthusiasm.

Kennedy was following him closely, while a frown of disapproval spread over Lockwood’s face.

“Then you know the secret of the hiding-place of the treasure?” queried Kennedy abruptly.

Whitney shook his head in the negative.  “It is my idea that we don’t have to know it,” he answered.  “With the hints that we have collected from the natives, I think we can locate it with the expenditure of comparatively little time and money.  Senor Mendoza has obtained the concession from the government to hunt for it on a large scale in the big mounds about Truxillo.  We know it is there.  Is not that enough?”

If it had been any one less than Whitney, we should probably have said it was not.  But it took more than that to deny anything he asserted.  Lockwood’s face was a study.  I cannot say that it betrayed anything except disapproval of the mere discussion of the subject.  In fact, it left me in doubt as to whether Whitney himself might not have been bluffing, in the certainty of finding the treasure—­perhaps had already the secret he denied having and was preparing to cover it up by stumbling on it, apparently, in some other way.  I recognized in Stuart Whitney as smooth an individual as ever we had encountered.  His was all the sincerity of a crook.  Yet he contrived to leave the whole matter in doubt.  Perhaps in this case he actually knew what he was talking about.

The telephone rang and Lockwood answered it.  Though he did not mention her name, I knew from his very tone and manner that it was Senorita de Mendoza who was calling up.  Evidently his continued absence had worried her.

“There’s absolutely nothing to worry about,” we heard him say.  “Nothing has changed.  I shall be up to see you as soon as I can get away from the office.”

There was an air of restraint about Lockwood’s remarks, not as though he were keeping anything from the Senorita, but as though he were reluctant for us to overhear anything about his affairs.

Lockwood had been smoking, too, and he added the stubs of his cigarettes to the pile in the ash-tray on Whitney’s desk.  Once I saw Craig cast a quick glance at the tray, and I understood that in some way he was anxious to have a chance to investigate those cigarettes.

“You saw the dagger which Norton brought back, did you not?” asked Kennedy of Whitney.

“Only as I saw the rest of the stuff after it was unpacked,” he replied easily.  “He brought back a great many interesting objects on this last trip.”

It was apparent that whether he actually knew anything about the secret of the Inca dagger or not, Whitney was not to be trapped into betraying it.  I had an idea that Lockwood was interested in knowing that fact, too.  At any rate, one could not be sure whether these two were perfectly frank with each other, or were playing a game for high stakes between themselves.