Mirrors and smoke: A. V. Hill, his Brigands, and the science of anti-aircraft gunnery in World War I.

In 1916 Captain A. V. Hill was transferred from the infantry to the Ministry of Munitions to work on anti-aircraft gunnery. He determined the three-dimensional coordinates of flying objects by placing two mirrors far apart. The mirrors were viewed from a fixed distance above them and observers simultaneously marked the position of the object. He gathered brilliant men, most too old or too young for conscription, who became known as Hill's Brigands. They determined the coordinates of the explosions of shots fired with different fuse settings and fitted them with the ballistic equations to construct accurate gunnery tables. They solved the puzzle of erratic fuse timing at high altitudes. They developed apparatus to locate aircraft by sound. Travelling groups of Brigands worked with anti-aircraft gunners, which Hill regarded as the dawn of operations research. Hill was as adept at leading scientists as he was at doing science.