“I’m afraid not,” laughed Mark, softly. “Bull had his chance once, but he failed to make the most of it.”

And at the words Bull seized his cousin convulsively by the arm and forced him back. Before the other could see what the yearling meant he had sprung forward, gasping with rage. The next instant the heavy door creaked and swung too.

Mark and his allies started back in alarm. Before they could make another move, before they could even think, they heard the rusty lock grate, heard a heavy log jammed against the door to hold it tight.

And then a low, mocking laugh of triumph rang on their ears. Bull Harris’ time had come at last.

CHAPTER XV.
BUYING THEIR RELEASE.

Our business just now is with Parson Stanard, the scholarly geologist and chemist, sitting all by himself in his silent tent and diligently analyzing his hematites and gottabites and outasights. The Parson made a curious figure; you would have laughed if you could have seen him. A solitary candle gave the flickering light by which he worked.

The Parson was a trifle agitated about that candle, because, as you know, it is the correct thing for a scholar to burn “midnight oil.” The midnight part was all right, but it took a long stretch of the imagination to convert tallow into kerosene. That kind of chemistry was too much for even the Parson.

However, it had to be borne. The Parson was seated in tailor fashion, in spite of which posture he was managing as usual to display his sea-green socks to the light. He had a row of bottles in a semicircle about him, like so many soldiers on parade; and at that moment he was engaged in examining a most interesting and complicated filtrate.

Parson Stanard was at the climax of his important night’s work. It will be remembered he was testing for potassium nitrate. He had it. He had put some of the substance in the fire and gotten the violet flame he wanted. Then, to make sure, he reached forward and took one of the bottles.