…it was found that although it was possible to enter the galleries very shortly after the various explosions, yet that directly an attempt was made to go on excavating, the gases confined in the debris escaped, causing nausea, and in one case insensibility.¹⁹

The standard issue of breathing apparatus for entering the gassy galleries, of which two types were described in the report, was primitive and of no use, and had probably been in store for many years as the rubber was perished. The Denayrouze respirator (see below), designed for entering only a short distance, was a long tube held in the mouth, fitted with a one-way valve which prevented exhaled air being re-inhaled. The air was not pumped, but had to be sucked in by the wearer. The one issued to the defenders was in too poor condition to be tried: ‘…it does not seem a very efficient arrangement, is most unpleasant to use, and unless each man had his own mouthpiece, most unhygienic.’²⁰

The other type, the Applegarth Aérophore, comprised a copper helmet, resembling that of a diver, to which was attached a water and gas-proof jacket. Air was fed into the helmet with a hand pump. The apparatus was not designed for walking stooped in a mine gallery and the window in the helmet, which also quickly became misted, prevented the wearer from seeing more than a few feet in front: ‘Captain Charles, who tried this apparatus, reports that he was very nearly stifled after about two minutes.’²¹

It was recommended that more upto-date rescue apparatus be obtained. The commander of the attacking force also recommended that the army again have specialist miners amongst its personnel: