Like Lord Armstrong, Bessemer turned his attention to the subject of the improvement of projectiles when there was a prospect of a European war in 1853. He invented a mode of firing elongated projectiles from smooth-bore guns, but received no countenance from the officials at Woolwich. Commander Minié, who had charge of the experiments which Bessemer was making on behalf of the Emperor of the French, said: 'Yes, the shots rotate properly; but if we cannot get something stronger for our guns, these heavy projectiles will be of little use.' This started Bessemer thinking and experimenting further, and led up, as we will see, to the great industrial revolution with which his name stands identified. He informed the Emperor that he intended to study the whole subject of metals suitable for artillery purposes. He built experimental works at St Pancras, but made many failures, furnace after furnace being pulled down and rebuilt. His prolonged and expensive experiments in getting a suitable ordnance metal were meanwhile using up his capital; but he was on the eve of a great discovery, and began to see that the refinement of iron might go on until pure malleable iron or steel could be obtained. His wife aided and encouraged him at this time as only a true wife can. After a year and a half, in which he patented many improvements in the existing systems of manufacture, it occurred to him to introduce a blast of atmospheric air into the fluid metal, whereby the cast-iron might be made malleable. He found that by blowing air through crude iron in a fluid state, it could thus be rendered malleable. He next tried the method of having the air blown from below by means of an air-engine. Molten iron being poured into the vessel, and air being forced in from below, resulted in a surprising combustion, and the iron in the vessel was transformed into steel. The introduction of oxygen through the fluid iron, induced a higher heat, and burned up the impurities. Feeling that he had succeeded in his experiment, he acquainted Mr George Rennie with the result. The latter said to him: 'This must not be hid under a bushel. The British Association meets next week at Cheltenham; if you have patented your invention, draw up an account of it in a paper, and have it read in Section G.' Accordingly Bessemer wrote an account of his process, and in August 1856, he read his paper before the British Association 'On the Manufacture of Malleable Iron and Steel without Fuel,' which startled the iron trade of the country. On the morning of the day on which his paper was to be read, Bessemer was sitting at breakfast in his hotel, when an iron-master to whom he was unknown, laughingly said to a friend: 'Do you know that there is somebody come down from London to read us a paper _on making steel from cast-iron without fuel_? Did you ever hear of such nonsense?'