Engrossed in argument, neither Maryon nor Nan noticed, the hum of a motor approaching up the drive, and when the door of the room was thrown open to admit Roger Trenby neither of them was able to repress a slight start.  Instantly a dark look of anger overspread Roger’s face as he advanced into the room.

“Good morning, Rooke,” he said, nodding briefly but not offering his hand.  “So the portrait is finished at last, I see.”

Nan glanced across at him anxiously.  There was something in his manner that filled her with a quick sense of apprehension.

“Not quite,” replied Rooke easily.  “I’m afraid we’ve been idling this morning.  There are still a few more touches I should like to add.”

Roger crossed the room, and, standing in front of the picture, surveyed it in silence.

“I think,” he said at last, “that I’m satisfied with it as it is. . . .  It will look very well in the gallery at Trenby.”

Rooke’s eyes narrowed suddenly.

“The portrait isn’t for sale,” he observed.

“Of course not—­to anyone other than myself,” replied Roger composedly.

“Not even to you, I’m afraid,” answered Rooke.  “I painted it for the great pleasure it gave me and not from any mercenary motive.”

Nan, watching the two men as they fenced, saw a sudden flash in Roger’s eyes and his under jaw thrust itself out in a manner with which she was only too familiar.

“Then may I ask what you intend to do with it?” he demanded.  There was something in the dead level of his tone which suggested a white-hot anger forcibly held in leash.

“I thought—­with Nan’s permission—­of exhibiting it first,” said Rooke placidly.  “After that, there is a wall in my house at Westminster where it would hang in an admirable light.”

The cool insolence of his manner acted like a lighted torch to gunpowder.  Roger swung round upon him furiously, his hands clenched, his forehead suddenly gnarled with knotted veins.

“By God, Rooke!” he exclaimed.  “You go too far! You will exhibit Nan’s portrait . . . you will hang it in your house! . . .  And you think I’ll stand by and tolerate such impertinence?  Understand . . .  Nan’s portrait hangs at Trenby Hall—­or nowhere!”

Rooke regarded him apparently unmoved.

“I’ve yet to learn the law which compels a man to part with his work,” he remarked indifferently.

Roger took an impetuous step towards him, his clenched hand raised as though to strike.

“You hound—­” he began hoarsely.

Nan rushed between them, catching the upraised hand.

“Roger! . . .  Roger!” she cried, her voice shrill with the fear that in another moment the two men would be at grips.

But he shook off her hand, flinging her aside with such force that she staggered helplessly backwards.

“As for you,” he thundered, his eyes blazing with concentrated anger, “it’s you I’ve to thank that any man should hold my future wife so cheap as to imagine he may paint her portrait and then keep it in his house as though it were his own! . . .  But I’m damned if he shall!”