"We can't do anything but make a stab at guessing," Frank told him. "One thing is certain--we've either got to turn tail and quit, or else----" "Plug it!" snapped Lanky decidedly. "Here, Frank, hold my light so I can kneel down and sight between those twin yellow spots." "It's a risky thing to do, Lanky. But, for one, I don't want to go back like a whipped cur, just because of a lone cat! Wait a minute! I've got an idea that may pay." He took the burning torch and started to fix one end in a crevice about six feet up from the rocky floor. "Bully for you, Frank! I get you," cried Lanky, grasping the idea in a flash. "Two guns ought to make surer work of the spitter than one. Now, count three when you've got your aim, and we'll fire together." At the word both reports rang out with a deafening concussion echoing and re-echoing along the passage. There was no attack, but the boys, as they pumped another cartridge into each gun chamber, could detect a strange shuffling noise. Then all became deathly still again. "Huh! got him that time, all right!" said Lanky triumphantly. While he took the torch and started forward, cautious Frank held his gun in readiness for immediate work. But there was no need of another shot, for they found a wolf of unusual size lying where it had fallen. "I'm sorry we had to do it," remarked Frank, "because it's a mother wolf, and like as not she's got a litter of whelps somewhere around here. If so be we happen to run across the bunch we'll have to knock them on the head, because they'll starve to death with the mother gone." As the boys ran across no sign of the wolf's den, however, it was concluded she must have had it in one of the numerous squatty side passages they had encountered every little while. These they could not have searched even had they wished, as they were too low to admit of their crawling through, though a wolf might be easily able to do so. Twice they fancied they had been in certain caverns before, because of familiar signs. So to avoid repetitions, they took to marking their passage and seeking fresh avenues for making progress. Hours passed in this way. Their stock of torch-wood was commencing to lower, and Frank began to wonder if they would not display wisdom by discontinuing the exploration of those bewildering caverns until the others of the party could join in the work. But there was so much fascination connected with the possibility of running upon what they sought at any moment, that he allowed himself to consent to Lanky's eager plea to "go on just a little further." Lanky, on his part, felt absolutely certain that they must be close to that mysterious five-fingered cave so plainly marked on the chart and would stumble on it soon. "We've got to eat sparingly of this cooked meat," advised Frank, as they sat on a broken stalactite that had fallen from the roof and partook of a "snack," their stomachs having been calling for food for some time.