aking omnibus is "_a_"
behind the traveller when he starts, and therefore goes "_a_ + _x_"
while he goes "_x_." Hence _a_ + _x_ = 5_x_; _i.e._ 4_x_ = _a_, and _x_
= _a_/4. This distance would be traversed by an omnibus in 15/4 minutes,
and therefore by the traveller in 5 x 15/4. Hence he is overtaken in
18-3/4 minutes after starting, _i.e._ in 6-1/4 minutes after meeting the
omnibus.

* * * * *

Four answers have been received, of which two are wrong. DINAH MITE
rightly states that the overtaking omnibus reached the point where they
met the other omnibus 5 minutes after they left, but wrongly concludes
that, going 5 times as fast, it would overtake them in another minute.
The travellers are 5-minutes-walk ahead of the omnibus, and must walk
1-4th of this distance farther before the omnibus overtakes them, which
will be 1-5th of the distance traversed by the omnibus in the same time:
this will require 1-1/4 minutes more. NOLENS VOLENS tries it by a
process like "Achilles and the Tortoise." He rightly states that, when
the overtaking omnibus leaves the gate, the travellers are 1-5th of
"_a_" ahead, and that it will take the omnibus 3 minutes to traverse
this distance; "during which time" the travellers, he tells us, go
1-15th of "_a_" (this should be 1-25th). The travellers being now 1-15th
of "_a_" ahead, he concludes that the work remaining to be done is for
the travellers to go 1-60th of "_a_," while the omnibus goes l-12th. The
_principle_ is correct, and might have been applied earlier.

CLASS LIST.

I.

BALBUS.
DELTA.

ANSWERS TO KNOT IX.

Sec. 1. THE BUCKETS.

_Problem._--Lardner states that a solid, immersed in a fluid, displaces
an amount equal to itself in bulk. How can this be true of a small
bucket floating in a larger one?

_Solution._--Lardner means, by "displaces," "occupies a space which
might be filled with water without any change in the surroundings." If
the portion of the floating bucket, which is above the water, could be
annihilated, and the rest of it transformed into water, the surrounding
water would not change its position: which agrees with Lardner's
statement.

* * * * *

Five answers have been received, none of which explains the difficulty
arising from the well-known fact that a floating body is the same weight
as the displaced fluid. HECLA says that "only that portion of the
smaller bucket which descen