My chief’s irritation soon subsided, and as soon as we were seated at a well-spread table he acquitted the Inspector handsomely.

“After all, I didn’t take Charles into my confidence, as I have taken you, Cassilis. But now we must set to work in earnest. What do you suggest as the next step?”

The question was too much for me, as I had to confess. Perhaps I was too much worried about the letters to be able to give my mind to anything else.

The consultant smiled good-naturedly.

“Our only clue to Captain Armstrong’s friend is his book. Books are produced by publishers, and publishers pay royalties. By this time the publisher of Across Sumatra ought to have heard from Armstrong’s executor. And the executor should be able to put us on the track of the person who has come into possession of his effects.”

He paused to let this reasoning sink into my mind before he added, “I think this greatly simplifies matters. It is much more likely that Armstrong kept some of the upasine himself among his trophies than that he gave it away, to a woman, above all. Depend upon it, we shall find that it passed on his death to the lady of the leopard’s claws.”

He seemed about to say more but broke off abruptly, as though a new thought had struck him. “She will have to be handled carefully,” was all he said after a short silence.

It was impossible for me to listen any longer without reminding him of the other task before us.

“Have you made any plans yet for the recovery of the letters?” I asked anxiously.

“Ah!” He gave me a shrewd look. “You are quite right to interest yourself in that business, my boy. It is more important to protect Lady Violet than even to detect Weathered’s murderer. The living come before the dead, eh? I am inclined to trust that part of the work to you.”