Outwardly the book accorded ill with its surroundings. In that place of desolation and death, it typified the petty neatness of office processes. Properly placed, it should have been found on a desk, with pens, rulers, and other paraphernalia forming exact angles or parallels to it. It was a quarto, bound in marbled paper, with black leather over the hinges. No external label suggested its ownership or uses, but through one corner, blackened and formidable in its contrast to the peaceful purposes of the volume, a hole had been bored. The agency of perforation was obvious. A bullet had made it.

"Seen something of life, I reckon," said Trendon, as the captain turned the volume about slowly in his hands.

"And of death," returned Captain Parkinson solemnly. "Do you know, Trendon, I almost dread to open this."

"Pshaw!" returned the other. "What is it to us?"

He threw the cover back. Neatly lettered on the inside, in the fine and slightly angular writing characteristic of the Teutonic scholar, was the legend:

Karl Augustus Schermerhorn,
1409-1/2 Spruce Street,
Philadelphia, Pa.

The opposite page was blank. Captain Parkinson turned half a dozen leaves.

"German!" he cried, in a note of disappointment, "Can you read German script?"

"After a fashion," replied the other. "Let's see. _Es wonnte sechs--und-- dreissig unterjacke_," he read. "Why, blast it, was the man running a haberdashery? What have three dozen undershirts to do with this?"

"A memorandum for outfitting, probably," suggested the captain. "Try here."

"Chemical formulae," said Trendon. "Pages of 'em. The devil! Can't make a thing of it."

"Well, here's something in English."

"Good," said the other. "_By combining the hyper-sulphate of iridium with the fumes arising from oxide of copper heated to 1000 C. and combining with picric acid in the proportions described in formula x 18, a reaction, the nature of which I have not fully determined, follows. This must be performed with extreme care owing to the unstable nature of the benzene compounds._"

"Picric acid? Benzene compounds? Those are high explosives," said Captain Parkinson. "We should have Barnett go over this."

"Here's a name under the formula. _Dr. A. Mardenter, Ann Arbor, Mich_. That explains its being in English. Probably copied from a letter."

"This must have been one of the experiments in the valley that Slade told us of," said the captain, thoughtfully. "Why, see here," he cried, with something like exultation. "That's what Dr. Schermerhorn was doing here. He has the clue to some explosive so terrific that he goes far out of the world to experiment with its manufacture. For companions he chooses a gang of cutthroats that the world would never miss in case anything went wrong. Possibly it was some trial of the finished product that started the eruption, even. Do you see?"

"Don't explain enough," grunted Trendon. "Deserted ship. Billy Edwards. Mysterious lights. Slade and his story. Any explosives in those? Good enough, far as it goes. Don't go far enough."

"It certainly leaves gaps," admitted the other.

He turned over a few more pages.

"Formulas, formulas, formulas. What's this? Here are some marginal annotations."

"Unbehasslich," read Trendon. "Let's see. That means 'highly unsatisfactory,' or words to that effect. Hi! Here's where the old man loses his temper. Listen: _'May the devil take Carroll and Crum for careless'_--h'm--well, _'pig-dogs.'_ Now, where do Carroll and Crum come in?"

"They're a firm of analytical chemists in Washington," said the captain. "When I was on the ordnance board I used to get their ............