Copy letter from Herbert Rix, to Messrs Harrison & Sons Asks the Messrs to make an electro of the figure illustrating Lord Kelvin [William Thomson] and Mr Erskine Murray's paper 'On Temperature Variation of the Thermal Conductivity of Rocks', read 30 May, and send it at once to the editor of 'Nature', inclosing the account for the same. 11 June 1895