air of the place where the coat habitually hangs. The graphite has obviously been picked up from a seat and the cocoa and hops from some factories that the man passes frequently, though I don't see why they are on the right side only."
"That is a question of time," said Thorndyke, "and incidentally throws some light on our friend's habits. Going from home, he passes the factories on his right; returning home, he passes them on his left, but they have then stopped work. However, the first group of substances is the more important as they indicate the locality of his dwelling—for he is clearly not a workman or factory employee. Now rice-starch, wheat-starch and a group of substances collectively designated 'spices' suggest a rice-mill, a flour-mill and a spice factory. Polton, may I trouble you for the Post Office Directory?"
He turned over the leaves of the "Trades" section and resumed: "I see there are four rice-mills in London, of which the largest is Carbutt's at Dockhead. Let us look at the spice-factories." He again turned over the leaves and read down the list of names. "There are six spice-grinders in London," said he. "One of them, Thomas Williams & Co., is at Dockhead. None of the others is near any rice-mill. The next question is as to the flour-mill. Let us see. Here are the names of several flour millers, but none of them
