Nell knew, vaguely, that the name Castle Turing was a hint; she'd learned 
a bit about Turing at Miss Matheson's Academy. He had something to do with 
computers. She could have turned to the Encyclopædia pages and looked it 
right up, but she had learned to let the Primer tell the story its own way. 
Clearly the soldiers were not men in armor, but simply wind-up men, and the 
same was probably true of the Duke of Turing himself.