the lane. When it got to a point about a hundred yards from the
road, at, I afterwards found, an S curve which cut off the view in
both directions, it stopped and the driver got down. I need not
tell you that I watched him carefully and, Merriman, what do you,
think I saw him do?"

"Change the number plate?" suggested Merriman with a smile.

"Change the number plate!" repeated Hilliard. "As I'm alive, that's
exactly what he did. First on one side and then on the other. He
changed the 4 to a 1. He took the 1 plates out of his pocket and
put the 4 plates back instead, and the whole thing just took a
couple of seconds, as if the plates slipped ln and out of a holder.
Then he hopped up into his place again and started off. What do you
think of that?"

"Goodness only knows," Merriman returned slowly. "An extraordinary
business."

"Isn't it? Well, that lorry went on out of sight. I waited there
until after six, and four more passed. About eleven o'clock No. 6
with the clean-shaven driver passed out, loaded, so far as I could
see, with firewood. That was the one that passed in empty at nine.
Then there was a pause until half past two, when your friend returned
with his lorry. It was empty this time, and it was still No. 1. But
I'm blessed, Merriman, if he didn't stop at the same place and change
the number back to 4!"

"Lord!" said Merriman tersely, now almost as much interested as his
friend.