forward the subdued noise became louder, and finally they could feel the vibration of machinery.
"This is the place," whispered Mr. Jenks. "That sound we hear is one of the mixing machines, for grinding the materials—carbon and the other substances—which go to make up the diamonds. I remember hearing that when I was in the cave before."
"Then we must be near the place," observed Tom.
"Yes, but I didn't have much chance to look around when I was here before. They wouldn't let me. I never even knew of the small cave Bill took us to."
"Well, if we're close to it, we'd better go cautiously, and not talk any more than we're obliged to," suggested Mr. Parker, and they agreed that this was good advice.
They walked on softly. Suddenly Tom, who was in the lead, saw a gleam of light.
"We're here," he whispered. "I'll put out our lantern, now," which he did. Then, stealing forward he and the others beheld a curious sight. The tunnel they were in ended at a small hole which opened into a large cavern, and, fortunately, this opening was concealed from the view of those in the main place.
