"There are many things I can say," he said. "In the first place, you have no authority to arrest anybody. You're not a police officer but only an American amateur."

"American, yes; but amateur, no," said Beale gently. "As to the authority, why I guess I can arrest you first and get the authority after."

"On what charge?" demanded Milsom, "there is nothing secret about this place, except Doctor van Heerden's association with it--a professional man is debarred from mixing in commercial affairs. Is it a crime to run a----"

He looked to van Heerden.

"A germicide factory," said van Heerden promptly.

"Suppose I know the character of this laboratory?" asked Beale quietly.

"Carry that kind of story to the police and see what steps they will take," said van Heerden scornfully. "My dear Mr. Beale, as I have told you once before, you have been reading too much exciting detective fiction."

"Very likely," he said, "but anyhow the little story that enthralls me just now is called the Green Terror, and I'm looking to you to supply a few of the missing pages. And I think you'll do it."

The doctor was lighting a cigarette, and he looked at the other over the flaring match with a gleam of malicious amusement in his eyes.

"Your romantic fancies would exasperate me, but for your evident sincerity. Having stolen my bride you seem anxious to steal my reputation," he said mockingly.

"That," said Beale, slipping off the bench and standing, hands on hips, before the doctor, "would take a bit of finding. I tell you, van Heerden, that I'm going to call your bluff. I shall place this factory in the hands of the police, and I am going to call in the greatest scientists in England, France and America, to prove the charge I shall make against you on the strength of this!"

He held up between his forefinger and thumb a crystal tube, filled to its seal with something that looked like green sawdust.

"The world, the sceptical world, shall know the hell you are preparing for them." Stanford Beale's voice trembled with passion and his face was dark with the thought of a crime so monstrous that even the outrageous treatment of a woman who was more to him than all the world was for the moment obliterated from his mind in the contemplation of the danger which threatened humanity.

"You say that the police and even the government of this country will dismiss my charge as being too fantastic for belief. You shall have the satisfaction of knowing that you are right. They think I am mad--but I will convince them! In this tube lies the destruction of all your fondest dreams, van Heerden. To realize those dreams you have murdered two men. For these you killed John Millinborn and the man Predeaux. But you shall not----"

"_Bang!_"

The explosion roared thunderously in the confined space of the vault.

Beale felt the wind of the bullet and turned, pistol upraised.

CHAPTER XXVI

THE SECRET OF THE GREEN RUST

A dishevelled figure stood by the boxes, revolver in hand--it was Bridgers, the man he had left strapped and bound in the "ambulance-room," and Beale cursed the folly which had induced him to leave the revolver behind.

"I'll fix you--you brute!" screamed Bridgers, "get away from him--ah!"

Beale's hand flew up, a pencil of flame quivered and again the vault trembled to the deafening report.

But Bridgers had dropped to cover. Again he shot, this time with unexpected effect. The bullet struck the fuse-box on the opposite wall and all the lights went out.

Beale was still holding the glass tube, and this Milsom had seen. Quick as thought he hurled himself upon the detective, his big, powerful hands gripped the other's wrist and wrenched it round.

Beale set his teeth and manoeuvred for a lock grip, but he was badly placed, pressed as he was against the edge of the bench. He felt van Heerden's fingers clawing at his hand and the tube was torn away.

Then somebody pulled the revolver from the other hand and there was a scamper of feet. He groped his way through the blackness and ran into the pile of boxes. A bullet whizzed past him from the half-crazy Bridgers, but that was a risk he had to take. He heard the squeak of an opening door and stumbled blindly in its direction. Presently he found it. He had watched the other men go out and discovered the steps--two minutes later he was in the street.

There was no sign of either of the two men. He found a policeman after he had walked half a mile, but that intelligent officer could not leave his beat and advised him to go to the police station. It was an excellent suggestion, for although the sergeant on duty was wholly unresponsive there was a telephone, and at the end of the telephone in his little Haymarket flat, a Superintendent McNorton, the mention of whose very name galvanized the police office to activity.

"I have found the factory I've been looking for, McNorton," said Beale.

"I'll explain the whole thing to you in the morning. What I want now is a search made of the premises."

"We can't do that without a magistrate's warrant," said McNorton's voice, "but what we can do is to guard the premises until the warrant is obtained. Ask the station sergeant to speak on the 'phone--by the way, how is Miss Cresswell, better, I hope?"

"Much better," said the young man shortly.

It was unbelievable that she could ever fill his heart with the ache which came at the mention of her name.

He made way for the station sergeant and later accompanied four men back to the laboratory. They found all the doors closed. Beale scaled the wall but failed to find a way in. He rejoined the sergeant on the other side of the wall.

"What is the name of this street?" he asked.

"Playbury Street, sir--this used to be Henderson's Wine Vaults in my younger days."

Beale jotted down the address and finding a taxi drove back to the police station, wearied and sick at heart.

He arrived in time to be a witness to a curious scene. In the centre of the charge-room and facing the sergeant's desk was a man of middle age, shabbily dressed, but bearing the indefinable air of one who had seen better days. The grey hair was carefully brushed from the familiar face and gave him that venerable appearance which pale eyes and a pair of thin straight lips (curled now in an amused smile) did their best to discount.

By his side stood his captor, a station detective, a bored and apathetic man.

"It seems," the prisoner was saying, as Stanford Beale came noiselessly into the room, "it seems that under this detestable system of police espionage, a fellow may not even take a walk in the cool of the morning."

His voice was that of an educated man, his drawling address spoke of his confidence.

"Now look here, Parson," said the station sergeant, in that friendly tone which the police adopt when dealing with their pet criminals, "you know as well as I do that under the Prevention of Crimes Act you, an old lag, are liable to be arrested if you are seen in any suspicious circumstances--you oughtn't to be wandering about the streets in the middle of the night, and if you do, why you mustn't kick because you're pinched--anything found on him, Smith?"

"No, sergeant--he was just mouching round, so I pulled him in."

"Where are you living now, Parson?"

The man with extravagant care searched his pockets.

"I have inadvertently left my card-case with my coiner's outfit," he said gravely, "but a wire addressed to the Doss House, Mine Street, Paddington, will find me--but I don't think I should try. At this moment I enjoy the protection of the law. In four days' time I shall be on the ocean--why, Mr. Beale?"

Mr. Beale smiled.

"Hullo, Parson--I thought you had sailed to-day."

"The first-class berths are all taken and I will not travel to Australia with the common herd."

He turned to the astonished sergeant.