“Oh, I say, you know, you gave me quite a start,” he jested. “I thought that you were going to set London on fire, and you simply seem to be taking your blood-pressure.”

Edestone still paid not the slightest attention to him, but after glancing about the room walked over to the mantelpiece where he picked up an old twelve-inch cannon-ball, which with considerable difficulty he brought back and placed on the table by the side of his instrument. His eyes once more roved about the room as if he were seeking something, and stepping deliberately to a passe-partout photograph of King George V., he ripped off the binding with his pocket-knife and tore from it the glass.

“Oh, I say, now, Mr. Edestone, those cow-boy methods don’t go here in London, and if you cannot behave a bit more like a gentleman, I’ll have you shown to the street.”

“We have more important matters on our hands just now, Mr. Underhill, than whether or not I am a gentleman,” snapped the American, his face set and serious as he with nervous fingers laid the glass on the table.

Rolling the cannon-ball to him, he lifted it very gently on to the glass plate, and then taking a key from his pocket he appeared to wind up on the inside of the instrument some mechanism which gave off a buzzing sound. Next he drew on a pair of rubber gloves with vulcanized rubber finger tips, and moistening with his lips the ends of the two platinum wires, pressed them to either side of the ball, first the one and then the other. A spark was given off when the second contact was made, and the room was filled with a pungent odour as of overheated metal which caused both men to cough violently.

Following this, with great care, and using only the tips of his fingers, he lifted the glass plate with the ball on it. When he had raised it his arm’s length above the table, like a plum pudding on a platter, he took the glass away, leaving the ball hanging unsupported in the air.

He sat down and smiled across the table into the astonished, almost incredulous, face of his companion.

“And now, Mr. Underhill, I hope you will pardon my rudeness,” he apologized lightly; “but I get so interested in these little tricks of mine that sometimes I forget myself. If you will permit me, I shall, when I go to Paris, order from Cartiers’s a more befitting frame for His Majesty, and shall beg you to accept it from me as a little souvenir of our meeting today.”

Underhill made no reply. His whole attention was riveted on that amazing ball, and Edestone, a trifle mischievously, added: “If you have a perfectly good heart, and think you can stand a bit of a shock, touch that ball lightly with your finger.”

“My heart’s all right, and I am prepared for anything,” Underhill surrendered, as he reached up and touched the innocent looking rusty old cannon-ball, whose only peculiarity seemed to be its willingness to remain where it was without any visible means of support.