I think of Dr Ketterley and an image rises up in my mind. It is the memory of a statue that stands in the nineteenth north-western hall. It is the statue of a man kneeling on his plinth; a sword lies at his side, its blade broken in five pieces. Roundabout lie other broken pieces, the remains of a sphere. The man has used his sword to shatter the sphere because he wanted to understand it, but now he finds that he has destroyed both sphere and sword. This puzzles him, but at the same time part of him refuses to accept that the sphere is broken and worthless, He has picked up some of the fragments and stares at them intently in the hope that they will eventually bring him new knowledge.