CHAPTER II
The Machine
When Carton hurried a little later for the second time down the long hall of the physics building of America University, his steps were quickened by the sight of a little knot of men outside the door of the rooms he had visited on the preceding day. There was Burns, his fellow-reporter of the _Courier_, two blue-clad policemen, and another man in plain clothes. All turned as he approached.
"Carton here saw it the same as I!" Burns was declaring. "He can tell you, Sergeant Wade!"
The detective-sergeant turned toward Carton, greeting him with a nod. He was familiar to the reporter, a sleepy-eyed, soft-moving man who chewed gum unceasingly and slowly.
"What is it I'm supposed to have seen?" Carton demanded. "And where's Dr. Grantham? And what's happened?"
"One thing at a time, Carton," soothed the sergeant. "Dr. Grantham's had a nasty crack on the head, and a doctor's in there fixing him up. In the meantime Burns here has been telling me a story about this Grantham making something invisible here yesterday with some machine?"
"Don't you read the papers, Wade?" Carton asked. "If you did, you'd have read last night that Dr. Grantham did just that."
"I never read what you fellows write," the detective assured him. "And I think I'll do so even less from now on. Making things invisible--you two haven't had any cracks on the head, have you?"
"Laugh on, ignorance," Carton told him as the other smiled slowly. "You're the sap, Wade, not to believe it. Grantham pulled the thing not only in front of three of us but also in front of President Ellsworth of the university himself."
"President Ellsworth, eh?" queried Wade keenly. "Same that's in there with Grantham now."
"In there?" they both asked, and the detective nodded. "Yes, it seems he was the one that found Grantham. And you say he saw this stunt pulled the same as you?"
He seemed to consider that. Carton was about to riddle him with questions when the door opened and an elderly man beckoned them inside. Carton and Burns slipped in with Sergeant Wade, and found Grantham leaning back in a chair with a thick bandage round his head, his eyes half-closed, and President Ellsworth bending anxiously over him. The doctor who beckoned them turned to the detective.
"Simple enough," he stated, "a blow on the skull with something blunt, more from the side than from behind. He says he was turning when it came--it probably saved him from concussion."
Who Did It?
Wade nodded quickly, and as the doctor passed out moved over to the seated scientist, Carton and Burns close behind him.
"Feeling better?" he asked. "Just take your time, Dr. Grantham--but we'd like to hear something about it."
"There's nothing to tell," said Grantham, spreading his hands helplessly. "Gray--that's my assistant--and I, had been working almost all day yesterday on a cabinet-projector of the light-curving force. We finished it after midnight, and then gave it its first tests on ourselves. It worked perfectly, as I had been sure it would, giving complete invisibility for either of us when the cabinet was strapped to his back."
"Just a moment," interrupted the detective. "Do you mean that this machine really made you or your assistant quite invisible?"
"Of course," the physicist said, with some wonder. "It was simply a larger development of the small projector we showed these reporters yesterday morning. When Gray wore it and turned it on he was absolutely invisible to me, and it was the same when I tested it. We were both very tired by then, and I told Gray he could go. When he had gone I was starting to lock up the projector for safe-keeping, when I heard a quick step behind me. I turned but was half-around when a crashing blow descended on my head. As I lost consciousness I felt the cabinet-projector being torn out of my hands, and then I knew nothing more until I awoke an hour ago with President Ellsworth bending over me."
Wade shifted his gum thoughtfully. "And you, sir?" to Ellsworth.
"I'm afraid I can tell you even less," said the President. "I knew Grantham was working late last night and wanted to see him. It must have been about three o'clock that I came in, and found him lying on the floor stunned. I called the doctor first, and then the police."
"You saw no one leaving when you entered?"
"No one."
"But isn't three in the morning a rather unusual time for you to visit your professors?" Wade asked.
President Ellsworth seemed somewhat perturbed at the question, glancing toward Grantham and then back to the detective. "My reason was a private one, but I have no objection to telling you of it. The fact is that I had become worried over this experiment or theory of Grantham's during the evening. While perfectly aware of his integrity, I realized that this work of his had a touch of the sensational that might reflect upon our institution, and I wanted to ask him to go slowly with the thing until his work was beyond any chance of criticism."
"Natural enough," Wade commented. "And what of this Gray? You said it was just after he left that you were struck from behind?"
"Yes, but that hardly makes him the criminal," said Grantham. "Gray has been absolutely devoted to this work of ours, and though somewhat silent and forbidding is quite reliable."
"You know where he lives?"
"Of course--not a thousand yards from here--in the rooming house diagonally opposite this corner of the campus."
Sergeant Wade turned to one of the blue-clad officers and spoke quickly to him. When the man had left he turned back to the physicist.
"This Gray, though, knew all about your projector just finished, something but a handful of people did. And since he had seen it make a man perfectly invisible, he must have been aware what powers its possession would give anyone who wanted to go in for criminal activities?"
"Anyone would have been aware of that," Dr. Grantham rejoined. "President Ellsworth remarked on it at our demonstration yesterday."
"You cannot say, however, that it is impossible that Gray, after leaving, crept back into the laboratory and struck you down and took the projector?" Wade pursued.
Gray Did Not Return
Dr. Grantham considered. "No," he said slowly, "but I would say that it sounds impossible to anyone who knew Gray."
Wade was silent, apparently revolving something in his mind, but before he could ask another question there entered the officer he had sent below, who spoke to him briefly in low tones. When he had done, Wade turned again to the physicist.
"How is it, then, that Gray did not return to his rooms when he left here, and has not been seen there since he left yesterday morning.”
"Good Lord!" Carton burst in excitedly. "Then it's Gray that--"
Dr. Grantham's face showed his astonishment and trouble. "Gray was not a criminal type," he persisted. "I simply cannot believe that it was he. More likely by far some thief who found the building's door open and who, seeing me about to lock up the projector, struck me down to get it."
"Well, Gray or another," Wade remarked, "someone is loose in New York at this moment with a thing which, if you're right, can give him the power to walk its streets unseen."
"But you'll endeavor to catch him?" President Ellsworth interposed anxiously. "I know but little about Grantham's mechanism, but surely it will be a terrible threat until whoever has it is captured?"
"We'll do what we can," Wade told him gloomily. "But it's going to be pretty hard to keep the force looking for someone they can't see! Even if they believe in the story at all. But I wouldn't worry about the thing, sir--visible or invisible, a crook can only keep free so long when thousands are concentrating on finding him."
"I sincerely hope you're right," said President Ellsworth as he turned to the door, hat in hand. "I'll see you tomorrow about it, Grantham--and take care of yourself until then."
When he had gone Dr. Grantham said quietly, "I am glad that he does not fully realize the appalling nature of this thing. I did not want to worry him to no purpose. Whether it was Gray who took the projector or another, is really immaterial now. The fact, the great fact, is that someone has it who has proved himself ruthless. And with it, he can loose such a terror upon New York--yes and upon the nation--as might be utterly without precedent!"
"One man?" asked Wade, skeptically.
"One man--but an invisible one!" Grantham exclaimed. "Have you realized what this means? It means that there are no limits to this man's power, whoever he is. It means that he can strike down any he wishes though that person surround himself with a thousand body-guards. It means that there is no fortress or strong-room that can keep him out, nothing that he cannot take for himself in full light of day. He can be, if he desires, an invisible tyrant ruling the world with terror!"
Wade's face was graver as he turned with Grantham, and with Carton and Burns to the door.
"Well, the most we can hope for now is to get him before he can use the thing," he said. "Whether it's Gray or another, we ought to be able somehow to----"
He halted, and his hand shot forward to a little table just inside the door. On it rested a big square white envelope addressed in a bold hand to "Dr. Grantham."
Wade's countenance was impassive as he grasped it. "This wasn't here when President Ellsworth left," he said. "I saw him take his hat from that table. Is that Gray's handwriting?"
"That or a good imitation of it," said Grantham slowly.
Who Came In
The detective turned to the two officers lounging outside the door. "Have you seen anyone come through this door since President Ellsworth left?" he asked them.
They shook their heads. "No one in or out since then."
Wade looked from Grantham to Carton and Burns for a moment, then handed the envelope to the former. The physicist tore it open and read silently the single sheet enclosed, then read aloud to the others.
_My dear Dr. Grantham:_
_It has amused me very much to hear your conversation with these worthy officers, but I really must be going. (You really should offer chairs to your guests, whether visible or invisible). I am obliged to you for developing the projector which now makes me invisible, but I warn you that any attempt on your part to regain it or to capture me will end disastrously for you. I am the Invisible Master, and I begin now my reign of this city. My rule of it will become evident to all in it soon, for in it from now onward my will shall be supreme._
_The Invisible Master._