Copy letter from James Hopwood Jeans, Secretary of the Royal Society; to Sir [James] Alfred Ewing, FRS Refers to a paper by [James Blacklock] Henderson and [H. R.] Hasse, 'A contribution to the thermodynamical theory of explosions', that Sir [James] Alfred Ewing communicated to the Society. Notes that the paper is estimated to print at 70 pages of 'Philosophical Transactions', owing to the large number of quotations from a Government document which was confidential during the war. Asks whether or not this document is now publicly available and, if so, if the author would be willing to replace these quotations with a mere reference to the document, and thereby greatly reduce it in length. 13 June 1921