British liquid fire attack - Public domain portrait photograph

Photograph shows liquid fire demonstration during King George V's visit to the Gas School, Helfaut, France, July 7, 1917 during World War I. (Source: Flickr Commons project, 2015 and similar image on Imperial War Museums website: http://www.iwm.org.uk/collections/item/object/205237727)
Title from data provided by the Bain News Service on the negative.
Photograph taken by Lieutenant John Warwick Brooke. (Source: Flickr Commons project, 2015)
Photograph published in The Sunday Oregonian, Sept. 30, 1917 with the caption: "When King George, Queen Mary and the Crown Prince visited the tommies fighting on the western front in France ..."
Forms part of: George Grantham Bain Collection (Library of Congress).
General information about the George Grantham Bain Collection is available at http://hdl.loc.gov/loc.pnp/pp.ggbain