“One-color cars a thing of the past! But that’s not all. If I switch on the car’s Pigmentizer like so, the car should . . . yes, yes, look at that!”

I watched with growing astonishment as the car started to fade in front of my eyes; the liquid crystal coating was emulating the background grays and browns of Mycroft’s workshop. Within a few seconds the car had blended itself perfectly into the background. I thought of the fun you could have with traffic wardens.

“I call it the ChameleoCar; quite fun, don’t you think?”

“Very.”

I put out my hand and touched the warm surface of the camouflaged Rolls-Royce. I was going to ask Mycroft if I could have the cloaking device fitted to my Speedster but I was too late; enthused by my interest he had trotted off to a large rolltop bureau and was beckoning me over excitedly.

“Translating carbon paper,” he announced breathlessly, pointing to several piles of brightly colored metallic film. “I call it Rosettionery. Allow me to demonstrate. We’ll start with a plain piece of paper, then put in a Spanish carbon, a second slip of paper—must get them the right way up!—then a Polish carbon, more paper, German and another sheet and finally French and the last sheet . . . there.”

He shuffled the bundle and laid it on the desk as I pulled up a chair.

“Write something on the first sheet. Anything you want.”

“Anything?”

Mycroft nodded so I wrote: Have you seen my dodo?

“Now what?”

Mycroft looked triumphant.

“Have a look, dear girl.”

I lifted off the top carbon and there, written in my own handwriting, were the words: ¿Ha visto mi dodo?

“But that’s amazing!”

“Thank you,” replied my Uncle. “Have a look at the next!”

I did. Beneath the Polish carbon was written: Gdzie jest moje dodo?

“I’m working on hieroglyphics and demotic,” Mycroft explained as I peeled off the German translation to read: Haben Sie mein Dodo gesehen? “The Mayan Codex version was trickier but I can’t manage Esperanto at all. Can’t think why.”

“This will have dozens of applications!” I exclaimed as I pulled off the last sheet to read, slightly disappointingly: Mon aardvark n’a pas de nez.

“Wait a moment, Uncle. My aardvark has no nose?”

Mycroft looked over my shoulder and grunted.

“You probably weren’t pressing hard enough. You’re police, aren’t you?”

“SpecOps, really.”

“Then this might interest you,” he announced, leading me off past more wondrous gadgets, the use of which I could only guess at. “I’m demonstrating this particular machine to the police technical advancement committee on Wednesday.”

He stopped next to a device that had a huge horn on it like an old gramophone. He cleared his throat.

“I call it my Olfactograph. It’s very simple. Since any bloodhound worth its salt will tell you that each person’s smell is unique like a thumbprint, then it follows that a machine that can recognize a felon’s individual smell must be of use where other forms of identification fail. A thief may wear gloves and a mask, but he can’t hide his scent.”