"Do be careful," implored Mrs. Raggles. "You won't be gone long, will you?"
"I will be back in a few minutes—if I come at all. I shall——"
Little Snap's speech ended with a startling exclamation.
CHAPTER IV.
WHAT LITTLE SNAP SAW.
Before entering the unknown dangers of the mysterious cave, Little Snap had seen that Jack was standing a short distance away, as complacently as might be.
"If I do not come back, Jack, go on to Daring's Diamond with the mail," he said, speaking as if to a human being.
The intelligent animal pricked up his ears, and answered with a low whinny.
The postboy's body was inside the mouth of the cavern when he had begun the speech to Mrs. Raggles.
It was too dark for him to see more than that the underground pathway descended at an angle of about forty-five degrees. But the moment his feet touched upon this portion of the rock he suddenly found himself slipping down the decline at a rapid rate.
In vain he threw out his hands to stop himself. The surface was like glass, over which he shot with the rapidity of lightning.