Billy and Frank followed his finger as he stood pointing on the edge of the excavation.
Slowly; as if some invisible hand was pushing it up on delicately-adjusted hinges—the big rock was swinging open from its sleep of the ages!
As it yawned wider and wider the first steps of a rough flight of stairs,—apparently cut out of the living rock,—were disclosed. From the aperture, as it gaped wider, rushed out a breath of air so fetid and poisonous that the boys grew sick and faint under its baleful odor.
CHAPTER XVI.
THE FIGURE ON THE CLIFF.
The boys held a hasty consultation as soon as they had retreated a safe distance from the reeking fumes of the Toltec excavation. Till the foul air of the place, probably stagnant for many hundred years, had been given a chance to pour out, it would have been folly to have wasted time on an attempt to descend into the black hole that the swinging back of the huge rock had revealed. There seemed to be little doubt, after the mystery had been discussed again and again, that Harry’s lucky shot had released some spring hidden in the quesal’s eye and caused the boulder to open. It seemed incredible;—but there was no other explanation, and it was decided to defer all discussion of the matter till a thorough examination could be made of the interior of the cavern they had stumbled upon for the hidden mechanism.
In the meantime a hasty camp was pitched, although there was little thought of sleep in the minds of any of the boys and after supper had been despatched they sat up long, with eyes that refused to grow drowsy, talking over what they were likely to find on their exploration trip, which they had agreed to undertake as soon as it grew light enough to make a start—always providing that the foul air of the place had cleared sufficiently to make such a thing feasible.
At Frank’s suggestion watches were finally set, the night being divided into three sections. Harry volunteered for the first, Frank for the second and Billy agreed to tackle the last. He was given the opportunity to select a short period of watching as both boys realized, although he indignantly disclaimed it, that he must be still feeling some effects of exhaustion from his wound.
Harry kept up a fire, for although it was not chilly the boys knew that once in a while a jaguar, bolder than his fellows, had been known to attack rubber-cutters, and they were by no means inclined to have the success of their expedition marred by anything approaching a tragedy. Having nothing better to do the lad amused himself by singing in a not particularly melodious way. Harry knew more about aeroplanes than he did of music and the tone effects he produced were something weird.
He had just attained a particularly high note and was congratulating himself—as is the way of people who have accomplished something they didn’t think they could do—when a sound that had startled both Frank and himself before, suddenly brought his satisfaction to an abrupt period.