Letter from H M [Hector Munro] Macdonald, Clare College, Cambridge, to [Joseph] Larmor As promised, Larmor will find enclosed [not present] necessary corrections in [William Mitchinson] Hick's investigations. He gives equations, writing that 'the boundary equations at the interface of the two media are the only limiting case of the volume ones'. He notes another way of looking at the problem with new variables introduced. With a pencilled draft reply or notes by Joseph Larmor. 1 February 1902