gone back and forth along this same route many times a week for years and years.

What influenced Donald and Adrian to accept of this sudden opportunity to spy on the Zuni medicine man it would be hard to say. Perhaps Donald, whose father was a mine operator as well as a big rancher, may have had a little notion that he would like to know more about the source of that precious metal which report said the old magician knocked from some wonderfully rich ledge inside the mountain nearby the village. That would not be so very strange after all, though the boy might be taking fearful risks in thus following such a vindictive old fellow as the Witch Doctor was reported to be.

As for Adrian, he did not have the same sort of temptation beckoning him on. In all probability the subject of mines and rich ore deposits would have failed to lure him; whereas the prospect of a pleasant little mystery to be solved would act as a spur.

And somehow, what Donald had told about that mysterious music, the strains of which often floated faintly to the ears of the Zuni people after their medicine man had betaken himself off to one of these famous audiences with Manitou, had taken a firm hold on the mind of Adrian. He hoped that before they quitted the country of the Zunis a chance would arise whereby they could find out if

there was really any truth in these stories; and should it prove to be so, learn just what caused the music that the ignorant natives believed supernatural or angel voices.

And as has already been said, Billie went along simply because he was afraid to stay there alone, and not that he felt any particular interest in either gold mines or cherub voices.

Two minutes later, and Donald held up a hand warningly. That was enough to tell the others he had sighted the object of their pursuit. And as they did not wish to let the hideous figure that stalked along ahead know how he was being followed, they hung back until their guide again beckoned them on.

“He’s just gone back of that line of brush yonder,” Donald whispered, as they joined him. “Let’s wait here a minute, to give him a chance to move along. And we can keep an eye on that cliff over yonder; because, unless I’m mistaken, he was heading that way when last I glimpsed him.”

They crouched there and waited, Billie nervously fingering his camera, as if in readiness to use it again should the chance arise.

“There he goes!” ejaculated Adrian, suddenly.