Your article, referring to rare earth elements including europium, dysprosium, gadolinium, praseodymium, holmium and ytterbium, was very enlightening (What are Ukraine’s critical minerals – and why does Trump want them?, 17 February). However, it was difficult for me to read, owing to the persistent intrusion of the earworm of a certain song by Tom Lehrer.
John O’Dwyer
Steeple Claydon, Buckinghamshire
• My favourite report (Letters, 18 February), from a history teacher, arrived before my interview at Cambridge: “His melancholy subversiveness will go down well with a certain type of don.” It didn’t. Or perhaps that particular don was elsewhere on the day. Happily, I ended up at Warwick, where EP Thompson bestrode the campus.
Nick Barton
Henstridge, Somerset
