• It was Sang-Hoon Kim at the Mokpo National Maritime University in South Korea who noted that the country is almost earthquake-free (23 July, p 34).
• The number of permutations of n particles each of which may be in m states is mn (Letters, 13 August).
• Francis Crick is reputed to have announced the discovery of the structure of DNA in Cambridge's Eagle pub (UK edition, 20 August, p 23).
