fted back to her natural position, head to wind.

"The only thing I can think of," said Priscilla, "is that the anchor
rope has got round the centreboard. It might. You never can tell exactly
what an anchor rope will do. However, if it has, we've nothing to do but
haul up the centreboard and clear it."

She took the centreboard rope and pulled. Frank joined her and they both
pulled. The centreboard remained immovable. The _Tortoise_ was entirely
unaffected by their pulling.

"Jammed," said Priscilla. "I feel a jolly sight less like that dove
than I did. It looks rather as if we were going to spend the day here.
I don't want to cut the rope and lose the anchor if I can possibly help
it, but of course it may come to that in the end, though even then I'm
not sure that we'll get clear."

"Can we do nothing?" said Frank.

"This," said Priscilla, "is a case for prolonged and cool-headed
reasoning. You reason your best and I'll bring all the resources of my
mind to bear on the problem!"

She sat down in the bottom of the boat and gazed thoughtfully at the
stone perch. Frank, to whom the nature of the problem was obscure, also
gazed at the stone perch, but without much hope of finding inspiration.
Priscilla looked round suddenly.

"We might try poking at it with the blade of an oar," she said. "I don't
think it will be much use, but there's no harm trying."

The poking was a total failure, and Priscilla, reaching far out to
thrust the oar well under the keel of the boat, very nearly fell
overboard. Frank caught her by the skirt at the last moment and hauled
her back.

"We'll have to sit down and think again," she said. "By the way, what
was that word which Euclid said when he suddenly found out how to
construct an isosceles triangle? He was in his bath at the time, as well
as I recollect."

A man is not in the lower sixth at Haileybury without possessing a good
working knowledge of the chief events of classical antiquity. Frank rose
to his opportunity.

"Are you thinking of Archimedes?" he asked. "What he said was 'Eureka'
and what he found out wasn't anything about triangles but--"

"Thanks," said Priscilla. "It doesn't really matter whether it was
Euclid or not and it isn't of the least importance what he found out.
It was the word I wanted. Let's agree that whichever of us Eureka's
it first stands up and shouts the word far across the sea. You've no
objection to that, I suppose. The idea may stimulate our imag