Possible Clues:

• In which mercurial activity takes place in the Tube?
• Temperature-measuring instrument
• With which the right temperature taken by me, amidst more shivering?
• Time that woman's doctor encountered ruler as measuring device
• Chef's device
• Cold shower?
• Mother accidentally encountered royalty with some measure of warmth
• Its mercurial rise may indicate need for care
• See me hotter, me out of sorts? Right -- get this!
• The writer put in revised other term for measuring device