"Always a saving, careful man," remarked Mrs. Keeley. "Oh, yes, quite well off—apart from his pension."
Matherfield glanced at Hetherwick, who had listened carefully to all that was asked and answered. Something in the glance seemed to invite him to take a hand.
"This occurs to me," said Hetherwick. He turned to Rhona. "Apart from this house-hunting, do you know whether your grandfather had any business affair in hand in London? What I'm thinking of is this—from what I saw of him in the train, he appeared to be an active, energetic man, not the sort of man who, because he'd retired, would sit down in absolute idleness. Do you know of anything that he thought of undertaking—any business he thought of joining?"
Rhona considered this question for a while.
"Not any business," she replied at last. "But there is something that may have to do with what you suggest. My grandfather had a hobby. He experimented in his spare time."
"What in?" asked Hetherwick. Then he suddenly remembered the stained fingers that he had noticed on the hands of both men the night before. "Was it chemicals?" he added quickly.
"Yes, in chemicals," she answered with a look of surprise. "How did you know that?"
"I noticed that his hands and fingers were stained," replied Hetherwick. "So were those of the man he was with. Well—but this something?"
"He had a little laboratory in our garden at Sellithwaite," she continued. "He spent all his spare time in it—he'd done that for years. Lately, I know, he'd been trying to invent or discover something—I don't know what. But just before we left Sellithwaite, he told me that he'd solved the problem, and when he was sorting out and packing up his papers he showed me a sealed envelope in which he said were the particulars of his big discovery—he said there was a potential fortune in it and that he should die a rich man. I saw him put that envelope in a pocket-book which he always carried with him."
"That would be the pocket-book I examined last night," said Matherfield. "There was no sealed envelope, nor one of which any seal had been broken, in that. There was nothing but letters, receipts and unimportant papers."