‘No,’ said Mechanus. ‘But every mechanico has so many motions he can make and no more. Then he has to go to the repair shop and be remade. If there is a mistake in his assembly, then he may have to go sooner.’

They came in a few moments to an unlit passageway which branched off at right angles.

‘What is down there?’ asked Raphael.

‘That is the repair shop,’ said the Sorcerer.

‘Oh,’ said Cassandra, ‘I don’t want to go there.’

It looked very dark down that corridor.

They walked on about a hundred yards to a door which the Sorcerer unlocked. When they stepped inside, they were in a gigantic warehouse full of metal cylinders and complicated electrical machines. The Sorcerer stopped, and they stood looking about them.

‘What are these things?’ asked Raphael.

‘These,’ said the Sorcerer proudly, ‘are what I particularly wished to show you. They are poison gas and death-ray machines.’

‘Oh,’ said Raphael, awed.