Second letter from John David Griffith Davies, to William Edward Curtis, regarding a paper 'Supersonic dispersion in gases II. Air containing water vapour' by M Mokhtar and E G Richardson Sectional Committee: Physics Sends a proof of the paper, but reminds him that it is classed as Confidential and will not be published until after the war. A limited number of prints will be available to Government Departments if necessary. Author's copies will only be available to a limited extent. The proposal is for one copy to be sent to each author, with further copies provided if they are reated with care and regarded as confidential. A limited number of copies will be printed and retained. Requests the quick return of the enclosed copy once corrected. [Published in the 'Proceedings of the Royal Society of London'] No received date. 29 February 1940