"I'll come there. They're watching this house. They have one man in front and one in back, a couple of detectaphones in my rooms here, and have coupled onto this telephone.
"Don't worry," he continued calmly as the other made an exclamation of dismay. "Talk ahead as loud as you please—they can't hear you. Do you think that those poor, ignorant flat feet can show me anything about electricity? I'd shoot a jolt along their wires that would burn their ears off if it weren't my cue to act the innocent and absorbed scientist. As it is, their instruments are all registering dense silence. I am deep in study right now, and can't be disturbed!"
"Can you get out?"
"Certainly. I have that same private entrance down beside the house wall and the same tunnel I used before. I'll see you in about fifteen minutes."
In Brookings' office, DuQuesne told of the constant surveillance over him.
"They suspect me on general principles, I think," he continued. "They are apparently trying to connect me with somebody. I don't think they suspect you at all, and they won't unless they get some better methods. I have devices fitted up to turn the lights off and on, raise and lower the windows, and even cast shadows at certain times. The housekeeper knows that when I go to my library after dinner, I have retired to study, and that it is as much as anyone's life is worth to disturb me. Also, I am well known to be firmly fixed in my habits, so it's easy to fool those detectives. Last night I went out and watched them. They hung around a couple of hours after my lights went out, then walked off together. I can dodge them any time and have all my nights free without their ever suspecting anything."
"Are you free tonight?"
"Yes. The time-switches are all set, and as long as I get back before daylight, so they can see me get up and go to work, it will be all right."
Brookings told him briefly of the failures to secure the solution and the plans, of the death of the three men sent to silence Shiro, and of all the other developments. DuQuesne listened, his face impassive.
"Well," he said as Brookings ceased. "I thought you would bull it, but not quite so badly. But there's no use whining now. I can't use my original plan of attack in force, as they are prepared and might be able to stand us off until the police could arrive."
He thought deeply for a time, then said, intensely:
"If I go into this thing, Brookings, I am in absolute command. Everything goes as I say. Understand?"
"Yes. It's up to you, now."
"All right, I think I've got it. Can you get me a Curtiss biplane in an hour, and a man about six feet tall who weighs about a hundred and sixty pounds? I want to drive the plane myself, and have the man, dressed in full leathers and hood, in the passenger's seat, shot so full of chloroform or dope that he will be completely unconscious for at least two hours."
"Easy. We can get you any kind of plane you want in an hour, and Perkins can find a man of that description who would be glad to have a dream at that price. But what's the idea?... Pardon me, I shouldn't have asked that," he added, as the saturnine chemist shot him a black look from beneath his heavy brows.
Well, within the hour, DuQuesne drove up to a private aviation field and found awaiting him a Curtiss biplane, whose attendant jumped into an automobile and sped away as he approached. He quickly donned a heavy leather suit, similar to the one Seaton always wore in the air, and drew the hood over his face. Then, after a searching look at the lean form of the unconscious man in the other seat, he was off, the plane climbing swiftly under his expert hand. He took a wide circle to the west and north.
Soon Shiro and the two guards, hearing the roar of an approaching airplane, looked out and saw what they supposed to be Crane's biplane coming down with terrific speed in an almost vertical nose-dive, as though the driver were in an extremity of haste. Flattening out just in time to avert destruction it taxied up the field almost to the house. The watchers saw a man recognizable as Seaton by his suit and his unmistakable physique stand up and wave both arms frantically, heard him shout hoarsely "... all of you ... out here," saw him point to Crane's apparently lifeless form and slump down in his seat. All three ran out to help the unconscious aviators, but just as they reached the machine there were three silenced reports and the three men fell to the ground. DuQuesne leaped lightly out of the machine and looked narrowly at the bodies at his feet. He saw that the two detectives were dead, but found with some chagrin that the Japanese still showed faint signs of life. He half drew his pistol to finish the job, but observing that the victim was probably fatally wounded he thrust it back into its holster and went on into the house. Drawing on rubber gloves he rapidly blew the door off the safe with nitro-glycerin and took out everything it contained. He set aside a roll of blueprints, numerous notebooks, some money and other valuables, and a small vial of solution—but of the larger bottle there was no trace. He then ransacked the entire house, from cellar to attic, with no better success. So cleverly was the entrance to the vault concealed in the basement wall that he failed to discover it.
"I might have expected this of Crane," he thought, half aloud, "after all the warning that fool Brookings persisted in giving him. This is the natural result of his nonsense. The rest of the solution is probably in the safest safe-deposit vault in the United States. But I've got their plans and notes, and enough solution for the present. I'll get the rest of it when I want it—there's more than one way to kill any cat that ever lived!"
Returning to the machine, DuQuesne calmly stepped over the bodies of the detectives and the unconscious form of the dying Japanese, who was uttering an occasional groan. He started the engine and took his seat. There was an increasing roar as he opened the throttle, and soon he descended upon the field from which he had set out. He noted that there was a man in an automobile at some distance from the hangar, evidently waiting to take care of the plane and his still unconscious passenger. Rapidly resuming his ordinary clothing, he stepped into his automobile and was soon back in his own rooms, poring over the blueprints and notebooks.
Seaton and Crane both felt that something was wrong when they approached the landing field and saw that the landing-lights were not burning, as they always were kept lighted whenever the plane was abroad after dark. By the dim light of the old moon Crane made a bumpy landing and they sprang from their seats and hastened toward the house. As they neared it they heard a faint moan and turned toward the sound, Seaton whipping out his electric torch with one hand and his automatic pistol with the other. At the sight that met their eyes, however, he hastily replaced the weapon and bent over Shiro, a touch assuring him that the other two were beyond the reach of help. Silently they picked up the injured man and carried him gently into his own room, barely glancing at the wrecked safe on the way. Seaton applied first-aid treatment to the ghastly wound in Shiro's head, which both men supposed to be certainly fatal, while Crane called a noted surgeon, asking him to come at once. He then telephoned the coroner, the police, and finally Prescott, with whom he held a long conversation.
Having done all in their power for the unfortunate man, they stood at his bedside, their anger all the more terrible for the fact that it was silent. Seaton stood with every muscle tense. He was seething with rage, his face purple and his eyes almost emitting sparks, his teeth clenched until the muscles of his jaws stood out in bands and lumps. His right hand, white-knuckled, gripped the butt of his pistol, while under his left the brass rail of the bed slowly bent under the intensity of his unconscious muscular effort. Crane stood still, apparently impassive, but with his face perfectly white and with every feature stern and cold as though cut from marble. Seaton was the first to speak.
"Mart," he gritted, his voice husky with fury, "a man who would leave another man alone to die after giving him that, ain't a man—he's a thing. If Shiro dies and we can ever find out who did it I'll shoot him with the biggest explosive charge I've got. No, I won't either, that'd be too sudden. I'll take him apart with my bare hands."
"We will find him, Dick," Crane replied in a level, deadly voice entirely unlike his usual tone. "That is one thing money can do. We will get him if money, influence, and detectives can do it."
The tension was relieved by the arrival of the surgeon and his two nurses,