"How did you know?"
Antony got up from the breakfast table and began to fill his pipe.
"I'm not sure that I can say, Bill. You know those problems in Algebra where you say, 'Let x be the answer,' and then you work it out and find what x is. Well, that's one way; and another way, which they never give you any marks for at school, is to guess the answer. Pretend the answer is 4—well, will that satisfy the conditions of the problem? No. Then try 6; and if 6 doesn't either, then what about 5?—and so on. Well, the Inspector and the Coroner and all that lot had guessed their answer, and it seemed to fit, but you and I knew it didn't really fit; there were several conditions in the problem which it didn't fit at all. So we knew that their answer was wrong, and we had to think of another—an answer which explained all the things which were puzzling us. Well, I happened to guess the right one. Got a match?"
Bill handed him a box, and he lit his pipe.
"Yes, but that doesn't quite do, old boy. Something must have put you on to it suddenly. By the way, I'll have my matches back, if you don't mind."
Antony laughed and took them out of his pocket.
"Sorry.... Well then, let's see if I can go through my own mind again, and tell you how I guessed it. First of all, the clothes."
"Yes?"
"To Cayley the clothes seemed an enormously important clue.
