“All the facts, therefore, pointed to John Blackmore as the person who occupied these chambers, and I accordingly adopted that view as a working hypothesis.”

“But this was all pure speculation,” objected Mr. Winwood.

“Not speculation,” said Thorndyke. “Hypothesis. It was ordinary inductive reasoning such as we employ in scientific research. I started with the purely tentative hypothesis that the person who signed the will was not Jeffrey Blackmore. I assumed this; and I may say that I did not believe it at the time, but merely adopted it as a proposition that was worth testing. I accordingly tested it, ‘Yes?’ or ‘No?’ with each new fact; but as each new fact said ‘Yes,’ and no fact said definitely ‘No,’ its probability increased rapidly by a sort of geometrical progression. The probabilities multiplied into one another. It is a perfectly sound method, for one knows that if a hypothesis be true, it will lead one, sooner or later, to a crucial fact by which its truth can be demonstrated.