"Valuable?" echoed Cleek, a queer, little one-sided smile flickering round his mouth. "I should just think it is valuable. Why, my dear chap, the Capitoline Venus is more than two thousand years old, and one of the most perfect and uninjured pieces of ancient art ever found. It was discovered in the eighteenth century, carefully bricked up in a cell of masonry, and wonderfully preserved. It is of almost priceless value. I only wonder that it was ever allowed out of the museum at Rome."

"I wish to goodness it hadn't been," groaned Mr. Narkom, wiping his heated brow.

"My dear Narkom," Cleek said, "for a heavy marble statue to melt into air is so preposterous that you may well call it supernatural. Tell me all the details, please. When was the loss discovered, and how?"

"The dickens of it is, there doesn't seem to be much to tell," said Narkom. "There hasn't been a sign of any suspicious character visiting the Institute since the exhibition was opened, and the number of plain-clothes men had been augmented. Not a door or window was touched, there was not the slightest sign of any struggle or upset, yet at nine-thirty this morning, when the secretary came to see about the dispatching of the statues to their respective owners, the Venus was missing. In front of the empty pedestal lay one of the commissionaires, Tom Scott—a member of the force really, only he was wearing the Institute uniform. He had evidently died——"

"What's that?" rapped out Cleek, spinning round in the chair in which he had just seated himself. "Do you mean he was murdered?"

"No," returned the Superintendent. "It was heart disease, so the doctor said. They fetched one in, and then made a quick tour round the building, to see where the burglars had made an entry, or whether any other articles of value were missing. But, as I said before, there isn't a hole or a crack big enough to let a mouse through."

"Hm! what about keys?" said Cleek. "This Scott—if he was out of the way, they could unbolt the doors and walk out."

"That's just it, Cleek. Every door save one has been screwed up, and on the outside. Scott was invariably locked in at night, the keys of the one door remaining with the secretary. Petrie and Hammond remained on duty outside all night, and they swear there was neither suspicious sight nor sound."

"The first thing is to come and look at the place for myself," said Cleek, quietly. "Who is at the head of affairs, by the way?"

"The Marquis of Willingsley is the president of the Institute with a whole host of bigwigs," replied Narkom; "but the man in charge is the secretary, Charles Belthouse, and he's nearly out of his mind over it."