excitement at where, in heaven's name, this underground adventure was going to end.
Round the bends they went, on and on into the depths of the chalk cliff, and the speedometer showed that they had now come a whole mile inland from the sea. The air was cold and damp and the breeze, that got stronger and stronger, blew the cobwebs to and fro high up in the roof and made Jeremy and Jemima huddle up together to keep warm.
And then, round a particularly sharp bend, they were suddenly faced with a blank wall of chalk that completely closed the cave. They had come to the end—or at any rate, they seemed to have come to the end—of the long cave!
But Commander Pott got out of the car and walked carefully forward, looking at the ground and the walls and then examining, inch by inch, the chalk wall that blocked the cave. He seemed to find something that excited him very much and he came back to the car and announced, "It's not a wall. It's some kind of a door, a sort of secret trap door. We must find the catch that opens it. Come on, everyone. We must just search every inch of the ground and the walls for it. It'll be something very clever I expect, and well hidden, so tell me if you find even the tiniest clue."
So, inch by inch, the family, working in the bright glare from CHITTY-CHITTY-BANG-BANG'S headlights, began examining what seemed to be a solid wall of chalk blocking the cave—just as if the original cave diggers had decided they couldn't be bothered to burrow any farther. The only clue, which Commander Pott found very early on, was that there was the tiniest crack that wandered, zigzagging, down the middle of the wall. It might have been natural, just a fault in the chalk surface, but again it might not, because through the crack a sharp draft was blowing from the other side.
Jemima had chosen to grub about in the right-hand corner where the wall met the side-wall of the cave. There were a lot of bits of flint embedded in the chalk. (There had been the whole way along the walls and roof of the cave, just like you find in the chalk of any chalk cliff. Some of them are fossils. It's often worth digging them out to see.) Jemima found a jagged piece of flint almost as big as a football. Some instinct made her tug at it and go on tugging until it suddenly came away in her hand so that she almost fell over backward. She bent down and peered into the hole the flint had left in the chalk and at once she gave a squawk .of excitement and called, "Daddy, come quickly!" And when Commander Pott knelt down beside her, he saw what she had seen—AN ELECTRIC LIGHT SWITCH!
"By golly, you're a clever girl, Jemima! I do believe you've found the secret." He called to the other two, "Stand back everyone. I'm going to press down this switch. Heaven only knows what'll happen. Ready?" And he pressed down the switch.
From somewhere inside the walls of the cave, there came a deep rumbling and grinding of machinery as, very slowly, the jagged zigzag crack in the solid wall widened and widened and widened until the two halves of what was really a secret door slid sideways into deep slots in the side walls of the cave. And what do you think CHITTY-CHITTY-BANG-BANG'S lights showed through the opening? A huge, vaulted room, quite as big as the inside of your village church, and all round the sides were cases and boxes and barrels and sacks neatly stacked up against the walls. It was an underground warehouse—a very secret warehouse for secret things. What could these things be? And who owned them? And why did the owners want to keep them secret? And why did they want a very private cave leading down through the cliff to the sea? And where were the owners? And, since it all smelled so strongly of secrecy, and therefore probably of unlawfulness, how nasty could these owners be?
These questions and many others ran through all their minds, and Commander Pott put their thoughts in a nutshell when he put his hands on his hips and declared, "Ho hum! I