“Diamonds and small wheels,” repeated Craven ruminating.  “Is that all that makes you think it the true explanation?”

“I don’t think it the true explanation,” replied the priest placidly; “but you said that nobody could connect the four things.  The true tale, of course, is something much more humdrum.  Glengyle had found, or thought he had found, precious stones on his estate.  Somebody had bamboozled him with those loose brilliants, saying they were found in the castle caverns.  The little wheels are some diamond-cutting affair.  He had to do the thing very roughly and in a small way, with the help of a few shepherds or rude fellows on these hills.  Snuff is the one great luxury of such Scotch shepherds; it’s the one thing with which you can bribe them.  They didn’t have candlesticks because they didn’t want them; they held the candles in their hands when they explored the caves.”

“Is that all?” asked Flambeau after a long pause.  “Have we got to the dull truth at last?”

“Oh, no,” said Father Brown.

As the wind died in the most distant pine woods with a long hoot as of mockery Father Brown, with an utterly impassive face, went on: 

“I only suggested that because you said one could not plausibly connect snuff with clockwork or candles with bright stones.  Ten false philosophies will fit the universe; ten false theories will fit Glengyle Castle.  But we want the real explanation of the castle and the universe.  But are there no other exhibits?”

Craven laughed, and Flambeau rose smiling to his feet and strolled down the long table.

“Items five, six, seven, etc.,” he said, “and certainly more varied than instructive.  A curious collection, not of lead pencils, but of the lead out of lead pencils.  A senseless stick of bamboo, with the top rather splintered.  It might be the instrument of the crime.  Only, there isn’t any crime.  The only other things are a few old missals and little Catholic pictures, which the Ogilvies kept, I suppose, from the Middle Ages—­their family pride being stronger than their Puritanism.  We only put them in the museum because they seem curiously cut about and defaced.”

The heady tempest without drove a dreadful wrack of clouds across Glengyle and threw the long room into darkness as Father Brown picked up the little illuminated pages to examine them.  He spoke before the drift of darkness had passed; but it was the voice of an utterly new man.

“Mr. Craven,” said he, talking like a man ten years younger, “you have got a legal warrant, haven’t you, to go up and examine that grave?  The sooner we do it the better, and get to the bottom of this horrible affair.  If I were you I should start now.”

“Now,” repeated the astonished detective, “and why now?”