"She went straight up from the old passage--through the men's door--she didn't trust you probably."

Milsom smiled wryly. Though he controlled these works and knew half the doctor's secrets, he suspected that the quantity of van Heerden's trust was not greatly in excess of his girl's.

"We'll wait," he said again, "there's no hurry and, anyway, I want to see you about old man Heyler."

"Von Heyler? I thought you were rid of him?" said van Heerden in surprise, "that is the old fool that Beale has been after. He has been trying to suck him dry, and has had two interviews with him. I told you to send him to Deans Folly. Bridgers would have taken care of him."

"Bridgers can look after nothing," said Milsom.

His eyes roved along the benches and stopped at a worker at the farther end of the room.

"He's quiet to-night," he said, "that fellow is too full of himself for my liking. Earlier in the evening before I arrived he pulled a gun on Schultz. He's too full of gunplay that fellow--excuse the idiom, but I was in the same tailor's shop at Portland Gaol as Ned Garrand, the Yankee bank-smasher."

Van Heerden made a gesture of impatience.

"About old Heyler," Milsom went on, "I know you think he's dangerous, so I've kept him here. There's a room where he can sleep, and he can take all the exercise he wants at night. But the old fool is restless--he's been asking me what is the object of his work."

"He's difficult. Twice he has nearly betrayed me. As I told you in the car, I gave him some experimental work to do and he brought the result to me--that was the sample which fell into Beale's hands."

"Mr. Beale is certainly a danger," said Milsom thoughtfully.

Van Heerden made a move toward the laboratory, but Milsom's big hand detained him.

"One minute, van Heerden," he said, "whilst you're here you'd better decide--when do we start dismantling? I've got to find some excuse to send these fellows away."

Van Heerden thought.

"In two days," he said, "that will give you time to clear. You can send the men--well, send them to Scotland, some out-of-the-way place where news doesn't travel. Tell them we're opening a new factory, and put them up at the local hotel."

Milsom inclined his head.

"That sounds easy," he said, "I could take charge of them until the time came to skip. One can get a boat at Greenock."

"I shall miss you," said van Heerden frankly, "you were necessary to me, Milsom. You're the driving force I wanted, and the only man of my class and calibre I can ever expect to meet, one who would go into this business with me."

They had reached the big vault and van Heerden stood regarding the scene of mental activity with something approaching complacency.

"There is a billion in process of creation," he said.

"I could never think in more than six figures," said Milsom, "and it is only under your cheering influence that I can stretch to seven. I am going to live in the Argentine, van Heerden. A house on a hill----"

The other shivered, but Milsom went on.

"A gorgeous palace of a house, alive with servants. A string band, a perfectly equipped laboratory where I can indulge my passion for research, a high-powered auto, wine of the rarest--ah!"

Van Heerden looked at his companion curiously.

"That appeals to you, does it? For me, the control of finance. Endless schemes of fortune; endless smashings of rivals, railways, ships, great industries juggled and shuffled--that is the life I plan."

"Fine!" said the other laconically.

They walked to a bench and the worker looked up and took off his mask.

He was an old man, and grinned toothlessly at van Heerden.

"Good evening, Signor Doctor," he said in Italian. "Science is long and life is short, signor."

He chuckled and, resuming his mask, returned to his work, ignoring the two men as though they had no existence.

"A little mad, old Castelli," said Milsom, "that's his one little piece--what crooked thing has he done?"

"None that I know," said the other carelessly; "he lost his wife and two daughters in the Messina earthquake. I picked him up cheap. He's a useful chemist."

They walked from bench to bench, but van Heerden's eyes continuously strayed to the door, behind which he pictured a caged Stanford Beale, awaiting his doom. The men were beginning to depart now. One by one they covered their instruments and their trays, slipped off their masks and overalls and disappeared through the door, upon which van Heerden's gaze was so often fixed. Their exit, however, would not take them near Beale's prison. A few paces along the corridor was another passage leading to the yard above, and it was by this way that Hilda Glaum had sped to the doctor's room.

Presently all were gone save one industrious worker, who sat peering through the eye-piece of his microscope, immovable.

"That's our friend Bridgers," said Milsom, "he's all lit up with the alkaloid of _Enythroxylon Coca_---- Well, Bridgers, nearly finished?"

"Huh!" grunted the man without turning.

Milsom shrugged his shoulders.

"We must let him finish what he's doing. He is quite oblivious to the presence of anybody when he has these fits of industry. By the way, the passing of our dear enemy"--he jerked his head to the passage door--"will make no change in your plans?"

"How?"

"You have no great anxiety to marry the widow?"

"None," said the doctor.

"And she isn't a widow yet."

It was not Milsom who spoke, but the man at the bench, the industrious worker whose eye was still at the microscope.

"Keep your comments to yourself," said van Heerden angrily, "finish your work and get out."

"I've finished."

The worker rose slowly and loosening the tapes of his mask pulled it off.

"My name is Beale," he said calmly, "I think we've met before. Don't move, Milsom, unless you want to save living-expenses--I'm a fairly quick shot when I'm annoyed."

Stanford Beale pushed back the microscope and seated himself on the edge of the bench.

"You addressed me as Bridgers," he said, "you will find Mr. Bridgers in a room behind that stack of boxes. The fact is he surprised me spying and was all for shooting me up, but I induced him to come into my private office, so to speak, and the rest was easy--he dopes, doesn't he? He hadn't the strength of a rat. However, that is all beside the point; Dr. van Heerden, what have you to say against my arresting you out of hand on a conspiracy charge?"

Van Heerden smiled contemptuously.