“Yes, it’s all one system,” replied Symon.  “It was all fitted up for the day His Royal Highness deposited the thing here.  You see, it’s locked up behind a glass case exactly as he left it.”

A glance showed that the arrangements for guarding the treasure were indeed as strong as they were simple.  A single pane of glass cut off one corner of the room, in an iron framework let into the rock walls and the wooden roof above; there was now no possibility of reopening the case without elaborate labor, except by breaking the glass, which would probably arouse the night watchman who was always within a few feet of it, even if he had fallen asleep.  A close examination would have showed many more ingenious safeguards; but the eye of the Rev. Thomas Twyford, at least, was already riveted on what interested him much more—­the dull silver disk which shone in the white light against a plain background of black velvet.

“St. Paul’s Penny, said to commemorate the visit of St. Paul to Britain, was probably preserved in this chapel until the eighth century,” Symon was saying in his clear but colorless voice.  “In the ninth century it is supposed to have been carried away by the barbarians, and it reappears, after the conversion of the northern Goths, in the possession of the royal family of Gothland.  His Royal Highness, the Duke of Gothland, retained it always in his own private custody, and when he decided to exhibit it to the public, placed it here with his own hand.  It was immediately sealed up in such a manner—­”

Unluckily at this point Summers Minor, whose attention had somewhat strayed from the religious wars of the ninth century, caught sight of a short length of wire appearing in a broken patch in the wall.  He precipitated himself at it, calling out, “I say, does that connect?”

It was evident that it did connect, for no sooner had the boy given it a twitch than the whole room went black, as if they had all been struck blind, and an instant afterward they heard the dull crash of the closing door.

“Well, you’ve done it now,” said Symon, in his tranquil fashion.  Then after a pause he added, “I suppose they’ll miss us sooner or later, and no doubt they can get it open; but it may take some little time.”

There was a silence, and then the unconquerable Stinks observed: 

“Rotten that I had to leave my electric torch.”

“I think,” said his uncle, with restraint, “that we are sufficiently convinced of your interest in electricity.”

Then after a pause he remarked, more amiably:  “I suppose if I regretted any of my own impedimenta, it would be the pipe.  Though, as a matter of fact, it’s not much fun smoking in the dark.  Everything seems different in the dark.”

“Everything is different in the dark,” said a third voice, that of the man who called himself a magician.  It was a very musical voice, and rather in contrast with his sinister and swarthy visage, which was now invisible.  “Perhaps you don’t know how terrible a truth that is.  All you see are pictures made by the sun, faces and furniture and flowers and trees.  The things themselves may be quite strange to you.  Something else may be standing now where you saw a table or a chair.  The face of your friend may be quite different in the dark.”