St. Paul daily globe. [volume] (Saint Paul, Minn.) 1884-1896, 1888-01-15


astonishing what a very simple query
will sometimes catch wise man nap
ping. Even the following have been
known to succeed:
'tHow many days would it take to cut
up piece of cloth fifty yards long, ore
yard being cut off every day?''
Or again:
"A snail climbing up post twenty
feet high ascends five feet every day
and slips down four feet every night
How long will the snail take to reach
the top of the poSt?"
Or again:
"A wise man having window one
yard high and one yard wide, and re-
quiring more light enlarged his window
to twice it's size, yet the window was
still only one yard high and one yard
wide. How was this dOne"'
as the preceding were catch questions
mond shaped at first and after
ward made square. AS to the two
former, perhaps it is scarcely neces-
sary seriously to point out that the
answer to the first is not SO days, but
40; and to the second not 90 days, but
16-since the snail gains one foot each
day for Is days, climbs on the sixteenth
day to the top of the pole and there re-
mains.
Such examples are plentiful. and occa-
sionally both curious and amusing, says
a writer in Temple Bar. There are Ger
tain problems which are in no way
catch questions (any problem involving
mere verbal bubble is, of course, out
of court by its own innate vileness), and
which, though at first sight extremely
simple, often require considerable inge-
nuity to arrive at a correct result. Take
for example the following: go
"a man walks round pole on the
top of which is monkey. AS the man
moves the monkey turns round on the
top of the pole SO as still to keep face to
face with the man. Query: When the
man has gone round the pole has he OF
has he not gone round the mOnkey?"
The answer which will occur at first
sight to most persons is that the man
has not gone round the monkey, since
he has never been behind it. The cor
rect answer, however, as decided by
knowledge, in the pages of which this
mOmentouS question has been argued,
is that the man has gone round the
monkey in going round the pole.
The following has not, so far as the
writer is aware, hitherto appeared in
print: "a train standing on an incline
is just kept stationary by an engine
which is not sufficiently powerful to
draw it up the incline. A second en-
CINE of the same power as the first is
then brought up to assist by pushing
the train from behind, and the two en-
gineS together take the train up the in
cline. Suppose the carriages to be linked
together by loose chains, so that when
the engine in front is acting the chains
are stretched and the buffers between
the carriages are Separated-then when
the train is moving under the action of
the two engines the buffers must be
either together or apart. Which are
they? If they are apart the engine be-
hind the train is evidently doing no
work. If they are together. then the
engine in front is doing none. But
neither engine alone can move the train,
Why, then, does the train mOve?'
The following was once asked at a
university wine party by now we'll
known senior wrangler: Suppose
ing the other by the tail, so that the
three form circle-then as the swal-
lowing process continues the circle evil
IDENTIFY grows smaller and smaller. Now,
if they thus continue to swallow each
other what will eventually become of
the snakeS?"
OF course it is clear that either the
swallowing process must stop some
where, or that the snakes will vanish
down each others Threats. At whaI
point. then, will the swallowing cease?
(which at any given moment is NOV
ing forward fastest the top of coach
wheel or the bottom?" To this very APP
parently simple question nine persons
out OF ten, asked at random,
viii give an incorrect reply. For
at first sight it appears evident
that both the top and the bottom of the
ward at the same rate, namely, the
speed at which the carriage is travelling.
But little thought will show that this
is far from being the case.
A POINT ON THE BOTTOM OF THE
is, in fact, by the direction of its mo-
tiOn round the axis, moving backward
in an opposite direction to that in
which the carriage is progressing and is
consequently stationary in space, while
point on the top of the wheel is NOV
ing forward with the double velocity of
its own motion round the axis and the
speed at which the carriage moves.
The following paradox, which has
given rise to much discussion. is some
what akin to the preceding: "HOw
can ship sail faster than the wind?''
Every yachtSman knows that ship
can sail faster than the wind; that is to
say, if the wind is blowing ten knots an
hour ship may be making twelve OF
fifteen knots an hour. Now, it is OBJ
vious that il the ship is sailing before
the wind it cannot, at the utmost, travel
faster than the wind itself is blowing as.
a matter of fact, it will travel much
more slowly. If, on the other hand, the
ship is sailing at an angle with the wind,
it seems at first sight that the wind must
act with less effect than before, but
more quickly than the wind is blowing.
This is paradox which few, even of
those who are well acquainted by expe-
rience with the fact, have found them
selves able to explain.
HLet us consider the difficulty in the
light of the following experiment:
Place q ball at one side of a billiard
table. and with the long cue held length
the ball across the cloth. The cue here
represents the wind, and the ball the
ship sailing directly before it: only as
there is here no waste of energy, which
in the case of the wind and ship is very
great, the ball, of course, travels at the
same rate as the cue, evidently it can
not possibly travel faster. Now, sup
pose a groove to be cut diagonally across
the table, from one corner pocket to the
other, in which the ball may roll. If
the ball be now placed at one end of the
groove and the cue held horizontally
and moved forward as before, the ball
will travel along the groove land along
the cue) in the same time as the
cue takes to move across the table.
This is the case of the ship sail
ing at an angle with the direc-