THE CANTERBURY PUZZLES
lated that the snail ascended 3 feet each day, sleeping and slipping
back 2 feet every night.
" Pray tell me," said the philosopher to his friend, who was in
the same line of business, " how long will it take Sir Snail to climb
to the top of the wall and descend the other side. The top of the
wall, as you know, has a sharp edge, so that when he gets there he
will instantly begin to descend, putting precisely the same exertion
into his daily climbing down as he did in his climbing up, and
sleeping and slipping at night as before/*
This is the true version of the puzzle, and my readers will
perhaps be interested in working out the exact number of days.
Of course, in a puzzle of this kind the day is always supposed to be
equally divided into twelve hours' daytime and twelve hours* night.
107.—
The Four Princes.
The dominions of a certain Eastern monarch formed a perfectly
square tract of country. It happened that the king one day
discovered that his four sons were not only plotting against each
other, but were in secret rebellion
against himself. After consulting
with his advisers he decided not to
exile the princes, but to confine them
to the four corners of the country,
where each should be given a trian-
gular territory of equal area, beyond
the boundaries of which they would
pass at the cost of their lives. Now,
the royal surveyor found himself con-
fronted by great natural difficulties,
owing to the wild character of the country. The result was that
while each was given exactly the same area, the four triangular dis-
tricts were all of different shapes, somewhat in the manner shown in
the illustration. The puzzle is to give the three measurements for
each of the four districts in the smallest possible numbers—all whole
furlongs. In other words, it is required to find (in the smallest
possible numbers) four rational right-angled triangles of equal area.
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