Letter from the Executive Secretary of the Royal Society on a paper 'The laminar boundary layer in compressible flow' by W F Cope and Douglas Rayner Hartree to P A Michaels, Sperry Rand Corportation The Royal Society doesn't preserve the typescripts of papers published in its journals. However there are indications that the paper was published without amendment. The 'revised date' doesn't appear at the top of the paper and the reports of the two referees don't suggest any amendments to the paper. [Published in Philosophical Transactions A, 1948]. 6 April 1971