ny laughed again and took him by the arm.

"You're a splendid conspirator, Bill. You and I could take on anything
together."

The pond was waiting for them, more solemn in the moonlight. The trees
which crowned the sloping bank on the far side of it were mysteriously
silent. It seemed that they had the world very much to themselves.

Almost unconsciously Antony spoke in a whisper.

"There's your tree, there's mine. As long as you don't move, there's no
chance of his seeing you. After he's gone, don't come out till I do. He
won't be here for a quarter of an hour or so, so don't be impatient."

"Righto," whispered Bill.

Antony gave him a nod and a smile, and they walked off to their posts.

The minutes went by slowly. To Antony, lying hidden in the undergrowth
at the foot of his tree, a new problem was presenting itself. Suppose
Cayley had to make more than one journey that night? He might come back
to find them in the boat; one of them, indeed, in the water. And if they
decided to wait in hiding, on the chance of Cayley coming back again,
what was the least time they could safely allow? Perhaps it would be
better to go round to the front of the house and watch for his return
there, the light in his bedroom, before conducting their experiments at
the pond. But then they might miss his second visit in this way, if he
made a second visit. It was difficult.

His eyes were fixed on the boat as he considered these things, and
suddenly, as if materialized from nowhere, Cayley was standing by the
boat. In his hand was a small brown bag.

Cayley put the bag in the bottom of the boat, stepped in, and using an
oar as a punt-pole, pushed slowly off. Then, very silently, he rowed
towards the middle of the pond.

He had stopped. The oars rested on the water. He picked up the bag from
between his feet, leant over the nose of the boat, and rested it lightly
on the water for a moment. Then he let go. It sank slowly. He waited
there, watching; afraid, perhaps, that it might rise again. Antony began
to count....

And now Cayley was back at his starting-place. He tied up the boat,
looked carefully round to see that he had left no traces behind him,
and then turned to the water again. For a long time, as it seemed to the
watchers, he stood there, very big, very silent, in the moonlight. At
last he seemed satisfied. Whatever his secret was, he had hidden it; and
so with a gentle sigh, as unmistakable to Antony as if he had heard