Correspondence with or concerning staff members of the Royal Observatory on active war service, covering pay, changes of address, commissions, operations, demobilisation and re-employment. There letters are foliated in one sequence, beginning with volumes for 1914-1916 and 1916-1918, and concluding with an envelope of loose letters for 1918-1919. The volumes have been incorrectly bound as part of the series of Annual Visitation Official Correspondence (formerly A6).