O'Hara. It was a theory of O'Hara's that he came to school to enjoy
himself. To have done any work during a mathematics lesson would have
struck him as a positive waste of time, especially as he was in Mr
Banks' class. Mr Banks was a master who simply cried out to be ragged.
Everything he did and said seemed to invite the members of his class to
amuse themselves, and they amused themselves accordingly. One of the
advantages of being under him was that it was possible to predict to a
nicety the moment when one would be sent out of the room. This was
found very convenient.

O'Hara's ally, Moriarty, was accustomed to take his mathematics with Mr
Morgan, whose room was directly opposite Mr Banks'. With Mr Morgan it
was not quite so easy to date one's expulsion from the room under
ordinary circumstances, and in the normal wear and tear of the
morning's work, but there was one particular action which could always
be relied upon to produce the desired result.

In one corner of the room stood a gigantic globe. The problem--how did
it get into the room?--was one that had exercised the minds of many
generations of Wrykinians. It was much too big to have come through the
door. Some thought that the block had been built round it, others that
it had been placed in the room in infancy, and had since grown. To
refer the question to Mr Morgan would, in six cases out of ten, mean
instant departure from the room. But to make the event certain, it was
necessary to grasp the globe firmly and spin it round on its axis. That
always proved successful. Mr Morgan would dash down from his dais,
address the offender in spirited terms, and give him his marching
orders at once and without further trouble.

Moriarty had arranged with O'Hara to set the globe rolling at ten sharp