ment a rain of falling
fragments of earth and wood came splashing down into the water--a few
stray pieces actually reaching the _Betty_, which rocked vigorously as
a minature tidal wave swept after us up the creek.

I put down my helm and brought her round so as to face the stricken
field.

"We seem to have done it, Joyce," I observed with some contentment.

She gave a little gasping sort of laugh. "It was splendid!" she said.
"But, oh, Neil, what appalling stuff it must be! It's blown up half
Canvey Island!"

"Never mind," I said cheerfully. "There are plenty of other islands
left. Let's get into the dinghy and see what the damage really amounts
to. I fancy it's fairly useful."

We anchored the _Betty_, and then pulled up the creek towards the
scene of the explosion, where a gaping aperture in the bank was
plainly visible. As we drew near I saw that it extended, roughly
speaking, in a half-circle of perhaps twenty yards diameter. The whole
of this, which had previously been a solid bank of grass and earth,
was now nothing but a muddy pool. Of the unfortunate tree which had
marked the site there was not a vestige remaining.

I regarded it all from the boat with the complacent pride of a
successful inventor. "It's even better than I expected, Joyce," I
said. "If one can do this with three-quarters of a pound, just fancy
the effect of a couple of hundredweight. It would shift half London."

Joyce nodded. "They'll be more anxious than ever to get hold of it,
when they know," she said. "What are you going to do? Write and tell
McMurtrie that you've succeeded?"

"I haven't quite decided," I answered. "I shall wait till tomorrow or
the next day, anyhow. I want to hear what Sonia has got to say first."
Then, backing away the boat, I added: "We'd better get out of this
as soon as we can. It's just possible some one may have heard the
explosion and come pushing along to find out what's the matter. People
are so horribly inquisitive."

Joyce laughed. "It would be rather awkward, wouldn't it? We couldn't
very well say it was an earthquake. It looks too neat and tidy."

Fortunately for us, if there was any one in the neighbourhood who
had heard the noise, they were either too lazy or too incurious to
investigate the cause. We got back on board the _Betty_ and took her
out into the main stream without seeing a sign of any one except
ourselves. The hull of the steam tramp was just visible in the far
distance, but except