Richard Rastall errs in his spherical trigonometry when he claims that he and his wife were further separated in Leeds and Dunedin universities than I with my wife in Christchurch and Vannes (Letters, March 5; February ).
Dunedin and Leeds are some 470km less separated than Christchurch and Vannes according to a map projecting New Zealand on its antipodes.
Couples split between, say, Spain and New Zealand might top our separation.
William Tobin
University of Canterbury Christchurch
New Zealand