"what have we here,
Willis?"

The inspector crossed over to the other, who was pointing to the
granolithic floor in front of him. One of the empty lorries was close to
the office wall, and the Frenchman stood between the two. On the floor
were three drops of some liquid.

"Can you smell them?" he inquired.

Willis knelt down and sniffed, then slowly got up again.

"Good man," he said, with a trace of excitement in his manner. "It's
brandy right enough."

"Yes," returned the other. "Security has made our nocturnal friend
careless. The stuff must have come from this lorry, I fancy."

They turned to the vehicle and examined it eagerly. For some time they
could see nothing remarkable, but presently it gave up its secret The
deck was double! Beneath it was a hollow space some six feet by nine
long, and not less than three inches deep. And not only so. This hollow
space was continued up under the unusually large and wide driver's seat,
save for a tiny receptacle for petrol. In a word the whole top of the
machine was a vast secret tank.

The men began measuring and calculating, and they soon found that no
less than one hundred and fifty gallons of liquid could be carried
therein.

"One hundred and fifty gallons of brandy per trip!" Willis ejaculated.
"Lord! It's no wonder they make it pay."

They next tackled the problem of how the tank was filled and emptied,
and at last their perseverance was rewarded. Behind the left trailing
wheel, under the framing, was a small hinged door about six inches
square and fastened by a spring operated by a mock rivet head. This
being opened, revealed a cavity containing a pipe connected to the tank
and fitted with a stop-cock and the half of a union coupling.

"The pipe which connects with that can't be far away," Laroche
suggested. "We might have a look round for it."

The obvious place was the wall of the office, which ran not more than
three feet from the vehicle. It was finished with vertical tongued and
V-jointed sheeting, and a comparatively short search revealed the
loose board the detectives were by this time expecting. Behind it was
concealed a pipe, jointed concertina-wise, and ending in the other half
of the union coupling. It was evident the joints would allow the half
coupling to be pulled out and connected with that on the lorry. The pipe
ran down through the floor, showing that the lorry could be emptied by
gravity.

"A good safe scheme," Laroche commented. "If I