The adventurers saw the reason a few seconds later. The image was visible only from one place, and that was directly looking up the valley. If one went too far to the right or left the head disappeared from view behind jutting crags, and it was impossible to see it from overhead, because the head was almost under a great spur of a mighty mountain.
“We might have hunted for it a week in the airship, and been directly over it,” said Tom, “and yet we would never have seen it.”
“Yes, but we never would have gotten here in such good shape if it hadn't been for your wonderful craft,” declared Mr. Jenks. “It brought us here safely and quickly, and enabled us to elude the men who tried to keep us back. We're here in spite of them. If we had traveled by train they might have interfered with us in a dozen ways.”
“That's so,” agreed Mr. Damon. “Well, now we're here, what's to be done? Which way do we start to reach the cave where the diamonds are manufactured, Mr. Jenks?”
“That I can't say. As you know, I only had a momentary glimpse of this stone head as they were taking me along the trail. Then one of the men noticed that the bandage had slipped and he pulled it into place. So I really can't say which direction to take now, in order to discover the secret.”
“How long after you saw the head before you reached the cave?” asked Tom. “In that way we may be able to tell how far away it is.”
“Well, I should say it was about two or three hours after I saw the head, before we got to the halting place, and I was carried into the cave. That would make it several miles from here, for we went in a wagon.”
“Yes, and they might have driven in a round-about way, in order to deceive you,” suggested Mr. Damon. “At best we have but a faint idea where the diamond cave is, but we must search for it; eh, Tom?”
“Certainly. We'll start right in. And as the airship will be of but little service to us now, I suggest that we leave it in this valley. It is very much secluded, and no one will harm it, I think. We can then start off prospecting, for I have a large portable tent, and we can carry enough food with us, with what game we can shoot, to enable us to live. I have a regular camping outfit on board.”
“Fine!” cried Mr. Parker, “and that will give me a chance to make some observations among the mountains, and perhaps I can predict when a landslide, or an eruption of some dormant volcano, may occur.”