WHEN George Appleby asked why – if flying was so safe – airports are called terminals (HAS, Jan 23) I was reminded of something similar from my boyhood.

While taking a summer stroll in the Forties a family friend asked me: “What keeps building bricks together?”

“Cement,” I replied, to which our friend said: “Ah, but if you look, you’ll see that it keeps them apart.”

LD Wilson, Guisborough, East Cleveland.