It was in the Professor's conception of things that when one is deceiving a fellow being one must talk the whole time. He is not the only one to suffer from that delusion.
He talked all the way to the billiard-room; he talked while McTaggart was pulling off the cloth; he talked while McTaggart was putting on the lights to see clearly on that dim January day; he talked while McTaggart was chalking his cue and thoughtfully placing the three balls in position.
The torrent of rapid words—all dealing with excellency at billiards, all squeaky—was interrupted only at one moment. It was the moment when McTaggart did what he had been expected to do—the moment when he took off his coat and threw it on the leather cushions by the side of his newly-made and slightly eccentric friend.
The sight of that coat so thrown immediately by his side, and subject to his hand, almost choked the senile conspirator with joy. But he recovered himself, and still poured out a torrent of repeated words as the young fellow walked slowly round the table, getting absorbed in a continuous break. The Professor interrupted that verbal spate only now and then to gaze with a murderous keenness at a projected stroke and to mutter "Marvellous!" two or three times; but all the while his heart was failing him. It was not the only mean thing he had done in his life by a long chalk. He had spent the whole of his life doing nothing but mean things; but it was the first actively and perhaps dangerously wrong thing the old booby had ever dared to do: for he did not count the Mullingar Diamond—that was in the cause of Science, and in the cause of Science you can do anything.
But the Devil chose his moment for him; it was a moment of silence when young McTaggart was waiting long and breathlessly to be certain of a stroke that would bring his break over the hundred. His back was turned to the Professor; he was intent upon his play.
The old bony hand, with the gesture of one that takes rather than gives, put the emerald into a side pocket of the coat, where lay he knew not what—but in point of fact, a tobacco pouch, a pipe, a pencil, and a piece of chocolate—of all things in the world!—no longer clean. Nor had the Emerald ever been in such society before, from the day when it had started life in the splendid court of Moscovy to these last evil days of ours.
McTaggart had brought off his shot: his break was 102, and the spot and the red lay perfect for a cannon and red in the pocket.
But you exaggerate the diplomatic value of the Professor if you think that he had the wit to continue his stream of gabble after the deed was done.
It was lucky for him that he was dealing with the candour of youth, or that abrupt retreat of his from the scene of his crime would have brought suspicion. For, his deed accomplished, he simply got up with a jerk, dropped all attention to the play, looked at his watch, muttered the time of day with an exclamation, and sidled out of the room, leaving his companion marooned ... and with him, full of success, went the Lesser Devil.
McTaggart could do without him; he went on playing for another ten minutes or so, till the break ended, and had reached the pretty figure of 151. Then he in turn looked at his watch in his waistcoat pocket, found it would be time for luncheon in a few minutes, put up his cue, and sadly resumed his coat.