Holmes smiled happily and reached over to clap the man on his shoulder. “I shouldn’t worry. By tomorrow, your two English visitors will have ceased to exist.”

The smaller man looked taken aback, then forced a grin. “And I’m supposed to find that reassuring?”

With that, the more clandestine portion of our interview was at an end. Nesbit led us inside to his study, where he opened the safe and took out a flat oilskin envelope and a japanned-tin box, laying both on his desk. The tin contained a crumpled and torn paper wrapping with an address in the government offices. Holmes laid the paper out on the desk and set to with the magnifying lens he carried always, but in the end, it told him little more than it had Nesbit: that some tidy person—a man, to judge by the printing—had parcelled up O’Hara’s amulet and sent it to Captain Nesbit, but as the address was entirely in capital letters, it had little personality.

“I couldn’t say if that was . . . our man’s writing,” Nesbit told us, his voice low and avoiding names, “but I’d lay money that it was a St Xavier’s boy who wrote it—the way he’s made the numerals is fairly distinctive. I went to the school myself for two years,” he explained. “Not at the same time, of course, but these numbers look like what I might do, were I attempting to conceal my hand.”

Holmes bent again over the paper, and when he stiffened at some characteristic invisible to me, standing at his shoulder, Nesbit said, “The sand, yes. Unfortunately, there’s nothing to set it apart—it might have come from anywhere in the country.”

“In London,” Holmes muttered, “I could say for a surety that a mite of soil had come from one spot or another, but in this vast land, there are ten thousand places where such grains might have come from.”

“Such as from another parcel,” I pointed out, unnecessarily. Holmes laid the paper back in the tin and took up the twine, turning his lens on its knots. But as they were not tied in a manner known only to Bolivian merchant sailors or a small tribe of gipsies from northern Persia, and since the fibres bore no traces of raw opium, gold dust, or a face-powder sold only in one exclusive shop in Paris, the string told him no more than the paper it had covered. Nesbit seemed mildly disappointed, but unsurprised. He put the box back into his safe, pulling out a lumpy envelope in return. Bringing it to the desk, he fished from it a pair of small silver lockets strung on copper-wire chains and handed us each one.