about it, or thought they did until the wayward genius of the Commander, who never pretended to be a chemist, taught them that there were permutations and combinations to the nth degree that they had never dared to think of.
"Wing-Commander Brock's great secret was originality. To the accepted formula he would add just a touch of the unexpected. The chemists would say it can't be done, or it wouldn't work. Sometimes it did not, but often it did, very nearly. And Brock's pioneer brain touched it a bit more—and lo! the impossible and the unexpected had arrived."
During his connection with the firm he had travelled over a large portion of the world on its behalf. His experience at a comparatively early age in organising and carrying out large displays—where the safety of thousands of spectators is in the hands of the directing mind—no doubt did much to develop those qualities of self-reliance and self-confidence which were so marked a characteristic of his Service career.
Wing-Commander Brock was responsible for many pyrotechnic inventions, and for the practical development of many ideas and inventions not his own, but which required technical knowledge and experience to ensure success.
It is perhaps as the "inventor of the smoke screen" that he is best known, a quite mistaken idea, the fallacy of which a moment's consideration will show. There are many references to the use of smoke as a screen in classic times and even in mythology. The smoke ball, as we have seen, was a recognised military store up to the middle of the last century. It is just as absurd to credit Commander Brock, or for that matter any living man, with the invention of the use of the smoke screen in warfare as to credit the inventor of a patent fire extinguisher with the idea of putting out fires.
What Commander Brock did do was to provide the means when the demand arose of producing smoke suited to the
