Letter from G H [George Henry] Livens, The University, Manchester, to [Joseph] Larmor His attempts at brevity have not brought out his difficulty. He explains, commencing with 'Let us consider the case of a thin circular cylindrical stream of a very diffuse but ionised gas projected towards the Earth in the equatorial plane...'. He notes the discrepency in his results but cannot decide which of two explanations is to be preferred. 18 June 1921