I’ll be accompanying some of the students from my school on a history trip to Ypres and a few other World War 1 battlefields in a few weeks’ time. Obviously, they’d much rather be learning chemistry, so I’ve been reading up on the different chemical agents used during World War 1, and this graphic is a byproduct of that. As it turns out, several of them were used for the first time at Ypres, so it’ll even be topical!