(1) Heaps of inflammable materials soaked with paraffin should be placed, if possible, at several points in front of the position. (2) A supply of the above materials should be kept stored in the shelters, so that the fire can be kept burning for about half an hour. (3) Every man should be supplied with special matches or other means of ignition which can be relied on in a wind. (4) Respirators must always be kept ready for use. (5) All oxygen apparatus must be maintained in a serviceable condition (Individuals who are equipped with such apparatus should be exercised in its use). ACTION TO BE TAKEN ON THE APPROACH OF A GAS CLOUD (1) A heavy fire should be opened with guns, machine guns, and rifles against the source of the gas cloud. (2) The fires should be lighted all along the front and kept burning. (3) The respirators should be firmly placed over nose and mouth as soon as the gas penetrates the position. (4) Breathing should only take place through the moistened respirator. (5) The gas cloud should be fanned upward by means of waterproof cloths (ten squares). CHAPTER XI SPOTTING I was to be a lucky man in that there were few branches of the war in which I did not have experience until a German bomb laid me low at Baupaume. I not only got an opportunity to do my country service in the air as a military observer, though it sent me on my first trip to a hospital, but not so very long afterward had the wildest and possibly more thrilling experience in command of one of his Majesty’s ground “dreadnoughts”--the famous tanks. Mind you, I wouldn’t paint myself as so brilliant and indispensable generally that the aviation corps was trying to steal me from the infantry and the special tank service from doing duty in the air. But it is to be recalled that I was a trained soldier--that I had had ten years of study and practice of military affairs. I must credit myself with always having been ambitious. And so, when war came I had several strings to my bow that must surely prove of value. One of these was the acquirement of an expert knowledge of wireless telegraphy and telegraphy generally. I had also picked up a considerable knowledge of photography. And naturally I knew gunnery. There was a dearth of men in the British air service at the time competent for an observer’s duty, scarcely more than half enough to man the hundreds of aëroplanes that were being turned out under forced pressure. For the battle of the Somme was now under preparation and it was not only desirable but imperative that Britain’s aviators should take the mastery of the air. Scores of other young officers like myself possessing special qualifications for the work were requisitioned from the other branches of the army and put into intensive training as aviation observers.