He lay tossing from side to side and
racking his brains to find a solution. He felt subconsciously that it
was within his reach, and yet he could not grasp it.

It was not far from dawn when a sudden idea flashed into his mind, and
he lay thrilled with excitement as he wondered if at last he held the
clue to the mystery. He went over the details in his mind, and the more
he thought over his theory the more likely it seemed to grow.

But how was he to test it? Daylight had come before he saw his way; but
at last he was satisfied, and at breakfast he told Willis his idea and
asked his help to carry out his plan.

"You're not a photographer, by any chance?" he asked.

"I'm not A1, but I dabble a bit at it."

"Good. That will save some trouble."

They called at a photographic outfitter's, and there, after making a
deposit, succeeded in hiring two large-size Kodaks for the day. With
these and a set of climbing irons they drove out along the Ferriby road,
arriving at the end of the lane to the works shortly after midday. There
they dismissed their taxi.

As soon as they were alone their actions became somewhat bewildering
to the uninitiated. Along one side of the road ran a seven-foot wall
bounding the plantation of a large villa. Over this Willis, with the
help of his friend, clambered. With some loose stones he built himself
a footing at the back, so that he could just look over the top. Then
having focused his camera for the middle of the road, he retired into
obscurity behind his defences.

His friend settled to his satisfaction, Hunt buckled on the climbing
irons, and crossing the road, proceeded to climb a telegraph pole
which stood opposite the lane. He fixed his camera to the lower
wires--carefully avoiding possible short-circuitings--and having focused
it for the center of the road, pulled a pair of pliers from his pocket
and endeavored to simulate, the actions of a lineman at work. By the
time these preparations were complete it was close on one o'clock.

Some half-hour later a large blue lorry came in sight bearing down along
the lane. Presently Hunt was able to see that the driver was Fox. He
made a prearranged sign to his accomplice behind the wall, and the
latter, camera in hand, stood up and peeped over. As the big vehicle
swung slowly round into the main road both men from their respective
positions photographed it. Hunt, indeed, rapidly changing the film, took
a second view as the machine retreated