In June 1915, he was transferred to France to serve as Geological Advisor to the Chief Engineer of the British Expeditionary Forces to establish potable water supplies from boreholes.

[5] King drew on his geological training to identify the source of aggregate present in the concrete used by the Germans to build their pillboxes.

The most senior of the three military geologists at the start of World War II, Major King was sent to France in 1939 where he later advised on suitable sites for airfields and the D-Day landings.

[7] King was released from the army in 1943, but his role was taken up by Captain (later Major) Frederick William Shotton (1906–1990) after his return from North Africa.

As stratigrapher has mapped and worked out the Upper Ordovician Shelly succession through Sedgwicks classic ground along the Welsh Borderland and in Ribblesdale.

A co-worker with Marr on Cambridgeshire gravels has successfully applied the Abbe Breuil's Somme Valley flint-implement typology in England.

The collection contains notebooks from World War II concerning water boreholes, rolls of maps, lantern plates marked "Channel", typed manuscripts, a presentation copy of "Work of Royal Engineers in the European War 1914-1919, Geological Work on the western Front 1922", handwritten notes on the retreat to Dunkirk, reports on specimens, dress medals, OBE and Military Cross; a silver cigarette case from colleagues at the Geological Survey 1916, certificates of honorary degrees and awards and a photograph album mostly relating to Sedgwick Club geological excursions.