He scowled. “It’s supposed to go bang. And it doesn’t.” He picked up a large lump hammer and hit the black box before him. Molly and I both flinched, and I wrestled the lump hammer away from the Armourer and put it down safely out of reach. His scowl deepened. “You have to teach technology to respect you! It needs to know who’s in charge!”

“You can try again later,” I said. “When we’re both safely out of range. Now, tell me about your new gadgets.”

“Yes, well . . . To start with, you’d better have this.” He took a heavy sheaf of handwritten papers out of his desk drawer and handed them to me. “This is your instruction manual for Merlin’s Glass. Don’t let anyone else see it. I wrote it all out in longhand so there’d be no record in the computers. Something this powerful needs to be kept strictly confidential.”

“There’s over forty pages here,” I said feebly.

“And more to come,” said the Armourer. “The damned thing’s full of extra options, many of which I don’t fully understand. Yet. Typical Merlin; couldn’t just make the Glass he was asked for . . . had to show off . . . These are just the options I’ve identified so far, along with the activating Words. And don’t go experimenting, Eddie; the thing’s probably full of booby traps for the unwary. It’s what I would have done. And Merlin Satanspawn was apparently renowned for his strange and unpleasant sense of humour.”

“You sure he wasn’t a Drood?” I said, thumbing quickly through the pages.

“Pay attention, Eddie. The two most useful options are these: the Glass can see everywhere in the present, as well as the past and the future, and it can also be used as a door, for immediate transport to anywhere in the world. Just tell it where you want to go, tug at the frame till it’s big enough, and then step through.”

I gave up on the pages, folded them neatly, and stuffed them into an inside pocket of my jacket. “Thank you, Uncle Jack. I’m sure it’ll be very helpful. But I was hoping for something a bit more . . . aggressive.”

“Hold everything,” said Molly. “If the Glass can show us scenes from absolutely everywhere in the present . . . we can use it to spy on people in the shower, or on the toilet! Maybe even take incriminating photographs! The possibilities for blackmail are endless!”

“You can take the witch out of the wood . . .” murmured the Armourer.

“Let’s test it!” said Molly. “Go on, you know you want to.”

I took the silver-framed hand mirror out of my pocket and hefted it thoughtfully in my hand. “I suppose we should try it out, in the spirit of scientific enquiry. Just to make sure it can do what it’s supposed to do.”

“That’s my boy!” the Armourer said cheerfully.