Professor Alan Dronsfield, from the University of Derby, explained in an entertaining and clear lecture how in WW1 the new methods used in the industrial production of fertilisers and explosives were more important to the outcome of the war (and to the numbers of killed and wounded) than the use of the better known poison gases. The British thought they could stop the Germans producing both fertilizers and explosives by blockading their imports of sodium nitrate “saltpetre” from Chile, but were ignorant of the newer developments in the German chemical industry. The process invented by Fritz Haber in 1909 to make ammonia from nitrogen in the air and hydrogen from water provided a cheap and inexhaustible route both to nitrate fertilizers and the recently invented “high” explosives like TNT. We learnt how they did this, and also witnessed a live demonstration of dyeing silk with madder. It was the 19th-century work on this dyestuff (crucially, carried out in Berlin), and the manufacture of a cheap synthetic version, that switched the dyestuffs industry from the UK to Germany, which then became the focus of the world’s production and, shortly later, a dynamic chemical industry that made possible the manufacture of high explosives on a huge scale. Alan’s talk was a perfect example of how two subjects can inform each other; it was also made local with photographs of the school’s WW1 memorial plaques in the chapel, and ended with images of the war accompanied by Barber’s Adagio for Strings.