Anthony bowed. “I see no reason to doubt the accuracy of your opinion.”

“Thank you, Mr. Bathurst.”

“But, all the same, I must confess to being mystified with regard to those footprints.”

“The whole affair is a mystery,” she answered, “that may never be solved.”

“Not the whole affair, Mrs. Prescott—some aspects are becoming increasingly plain—and I hope in time to solve it all!” Anthony’s jaw set.

“That will mean a lot to me, Mr. Bathurst,” she said. “Perhaps more than I can tell you.” She turned to Mary. “I’ll come with you now, dear, as you suggested. Good-bye to you two gentlemen. But there, I’m sure to see you again.” They passed out of the room together and left us.

“What are you doing this morning, Holmes?” I sallied. Anthony looked at me whimsically.

“I’m thinking of having another look at things,” he said; “there are one or two things I should like to make more sure of.”

“What are they?” I inquired curiously.

“I should like to have a look at the billiard room—and Prescott’s bedroom,” he replied unconcernedly. “I’m building up a theory and I would like to test it in one or two places. Come with me?”