Re your report (9 July), Nevil Shute’s 1947 novel The Chequer Board dealt with the question of racism when US forces were over here during the second world war, and my 1987 book When Jim Crow met John Bull: Black American Soldiers in World War II Britain is a comprehensive look at this unique experience. Several TV documentaries followed it, and the BBC made a feature film.
Graham Smith
Shrewsbury, Shropshire
• What I find irritating about Andrea Jenkyns’ impolite gesture (Report, 11 July) is that it was a US-style single finger. Surely as a Conservative she should uphold the traditional British two fingers? Black Friday, trick or treat, proms – where will it all end?
Ian Anderson
Cambridge
• I can accept longshore drift (Letters, 12 July), but how do stones in my flowerbeds rise up through the soil year after year, but drop to the bottom if thrown into the pond?
Mary McKeown
Biddenham, Bedfordshire
• A huge amount of academic effort has gone into understanding the Brazil nut effect, whereby muesli (or sand or asteroids) is sorted by shaking and granular convection. No longshore drift needed here.
Dr Steve Roser
Bristol
• Re late deliveries by Royal Mail ((Letters, 5 July), a postcard I sent my parents from New Zealand in April 1984 arrived in May 2011. Its first line read: “Time to break the silence.”
Brian Morrison
Edinburgh
• Have an opinion on anything you’ve read in the Guardian today? Please email us your letter and it will be considered for publication.