"No," Thorndyke agreed, "it was not a lens."
"And so cannot have been a spectacle-glass. But the surface was curved—one side convex and the other concave—and the little piece that remains of the original edge seems to have been ground to fit a bezel or frame. I should say that these are portions of a watch-glass."
"That is Polton's opinion," said Thorndyke, "and I think you are both wrong."
"What do you say to the glass of a miniature or locket?"
"That is rather more probable, but it is not my view."
"What do you think it is?" I asked. But Thorndyke was not to be drawn.
"I am submitting the problem for solution by my learned friend," he replied with an exasperating smile, and then added: "I don't say that you and Polton are wrong; only that I don't agree with you. Perhaps you had better make a note of the properties of this object, and consider it at your leisure when you are ruminating on the other data referring to the Blackmore case."
"My ruminations," I said, "always lead me back to the same point."
"But you mustn't let them," he replied. "Shuffle your data about. Invent hypotheses. Never mind if they seem rather wild. Don't put them aside on that account. Take the first hypothesis that you can invent and test it thoroughly with your facts. You will probably have to reject it, but you will be certain to have learned
