For answer he drew from his pocket a portion of an uneaten sandwich and placed it upon the table. Boyd, with his pocket-knife, cut off a piece of the meat, upon it sprinkled a grain or so of the mysterious powder, and threw it down to the hungry cat, which was mewing loudly, and purring round our legs. The thin creature, ravenously hungry, devoured it, but ere ten seconds had passed, and while we all three were watching attentively, it staggered, with a faint cry, and almost without a struggle rolled over, dead. "As I suspected," Boyd observed, turning to me. "This is the powder from the herbalist's." CHAPTER TWENTY ONE. UNDER THE LEADEN SEAL. "So far," continued Boyd, thoughtfully, pushing his hat to the back of his head, "we've proved one thing--that this stuff is poison." "Yes," I said. "But these photographs? Is it not extraordinary that we find them here among Eva's possessions?" "It's all extraordinary," he answered. "The letters more strange than anything," and he unlocked the third drawer expectantly, only, however, to find it contained something small wrapped in a piece of dirty wash-leather. He placed it before him, carefully opening it and disclosing something which caused us both to give vent to exclamations of surprise. Inside was a most commonplace object, yet to us it had a meaning peculiarly tragic--a single penny. Both of us recollected vividly the finding of a similar coin carefully wrapped in paper upon the body of the man at Phillimore Place, and there must, we decided, be some mysterious connexion between our two discoveries. "These letters," observed Boyd, putting aside the coin and its wrapping and taking up the correspondence he had been examining when I had found the box of mysterious powder, "they are all addressed to Miss Glaslyn, and in one only, as far as I can see, is her mother mentioned. They evidently refer to some deep secret." "Do you think the silence can refer to the affair at Kensington?" I suggested, holding one of the letters in my hand. "It's impossible to tell," he answered. "We have now the clearest proof that these letters were preserved in secret by Eva Glaslyn, together with some unknown but fatal drug, and the photographs of the victim. Therefore, if circumstantial evidence may be trusted, I should be inclined to believe that these letters refer to the matter which we are investigating. Perhaps, indeed, the peril mentioned in one of the letters refers to your own endeavours to fathom the mystery." "The whole thing is utterly bewildering," I said, re-reading the letter in my hand, a communication which certainly was of a most veiled character, evidently being type-written to disguise the writer's identity.