Related Clues:

• Rodent caught by the unusual mechanical device
• Mechanical device used by fantasy author, not the first or the last
• Gradually increase, with 'up'
• Device stopping backward motion
• Increase incrementally, with "up"
• Couple of scoundrels, second of which knocking out a tool
• Mechanical device that could make one chatter
• Chatter (anag.)
• Move by degrees in one direction only
• ... in earth, moving about hundred tons — it only allows travel in one direction
• Chatter about tool
• Gradually increase, with "up"