“The entrance to a subaground tunnel!” Greg shouted, leaping up and down in the edge of a wave.

He will say “subaground,” and it really is quite as sensible as some words.

“The entrance to a real pirate cave, you mean!” said Jerry.  “Glory, Chris, I really shouldn’t wonder if it were.  Captain Kidd was up and down the coast here.  What if they buried stuff in there and then propped a big chunk of rock up against the hole?”

“I wish we had a telescope,” I said, “though I don’t suppose we could see into the blackness with it.  Mercy, I wish we could get out there!  It’s more worth exploring than ever.”

“Let’s tell Mother and Aunt!” said Greg, and started running back down the beach, shouting something all the way.

Mother said, “Nonsense!” and, “Of course it’s a natural cave in the rock.  You probably only noticed it today.”

But she and Aunt Ailsa shut up the H.G.  Wells book and came to look.  They did think, when they saw it, that it was something new.  Aunt Ailsa thought it looked very exciting and mysterious, but she agreed with Mother that it was no sort of place to go to in a boat.

“Just look at the white foam flinging around those rocks,” she said; “and there’s practically no surf on today.”

We had to admit that it wasn’t a nice-looking place to land on from a rowboat, but we did wish that we were hardy adventuring men, bold of heart and undeterred by grown-ups.  We knew, too, that Captain Moss would say, “Pshaw!” if we told him there might be treasure on the Sea Monster, and he certainly wouldn’t risk the Jolly Nancy on those rocks in her nice new green paint.

We were so much excited about the Sea Monster suddenly having a big black hole in it that we almost forgot to take the bottle when we went home.  We did forget Aunt Ailsa’s hatpin, and Greg had to run back for it, because he can run faster than any of the rest of us, and Captain Lewis held the ferry for him.  Everybody leaned out from the rail and peered up the landing, because they thought it must be a fire or the President or something.  They all looked awfully disappointed when it was only Greg, with the black necktie still around his head and Aunt’s hatpin held very far away from him so that it wouldn’t hurt him if he fell down.  He tumbled on board just as the nice brown Portuguese man who works the rattley chain thing at the landings was pushing the collapsible gate shut, and Greg gasped: 

“I brought—­the moidores—­too!”

But Jerry collared him and pulled the necktie off his head.  Jerry hates to have his relatives look silly in public, but I thought Greg looked very nice.

We chucked the bottle overboard from the upper deck, just when the Wecanicut was halfway over.  The nice Portuguese man shouted up, “Hey!  You drop something?” but we told him it was just an old bottle we didn’t want, and not to mind.  We watched it go bob-bobbing along beside an old barrel-head that was floating by, and we wondered how far it would go, and if it would leak and sink.  The tide was exactly right to carry it outside, if all went well.