English: An unidentified soldier hoses down the gas trial chamber to help control the temperature. The demountable gas trial chamber MKII had plywood cladding and is covered with scaffolding and a tarpaulin. The chamber was used by the Australian Chemical Warfare Research and Experimental Section, later to be known as the 1st Field Trials Company, Royal Australian Engineers (RAE), and was designed by Hugh Ennor, Jack Legge and refrigeration engineer Walter Bassett, in Melbourne. It was a 100 cubic metre stainless steel chamber, and was air conditioned to control effects of the northern heat and humidity for more accurate testing of chemical warfare gases on human volunteers. Despite the sophisticated refrigeration design, the chamber was directly influenced by the heat of the sun. During testing the volunteers exercised vigorously (moving sacks) usually for up to an hour, wearing respirators and sometimes with protective ointment and impregnated clothing. Without sophisticated instruments to control the release of the gas, Major Freddie Gorrill (Commanding Officer) used a makeshift method to generate a concentration of gas. Concentrations were achieved by volatising an amount of dichlorodiethylsulfide (mustard gas). The chemical was spread on blotting paper, placed on an electric hotplate, and distributed with the aid of a fan. When the volunteers left the chamber the heat and humidity outside multiplied the effect of the chemicals on their clothes and skin. Note the four Porton bubblers in the left foreground. On the right next to the tarpaulin are injector boxes with one of their accompanying gas cylinder visible to the left of the soldier. The handles of more bubblers are visible behind the injector boxes.