When was poison gas first made?
How Stuff Works. "How Biological and Chemical Warfare Works."
January 2003). Roman Legions regularly used burning sulphur (SO2,
SO3, H2S, H2SO4(in rain/fog) to at least irritate, incapacitate, or
at best, kill enemies in immobile situations; fortified towns,
settlements against geographic barriers; islands, cliffs, bodies of
water, etc. Opinions differ as to whether the Legions developed
poison gas themselves, or if their own survivors/allies reported
how to use it after hard experience. Similarly, opinions differ
about the logistics and practicality of raw sulphur transport, and
the (un)liklihood of a somewhat bulky(and nasty)materiel being
cheerfully carried by a notoriously lightly-packed Legionnaire. It
is possible that free, native, naturally-occurring sulphur deposits
were scouted, as would have been other staples, like water, wood,
game, etc., and if present, utilized, from a point upwind any