Before the eruption of Krakatoa in 1883, nobody knew about the invisible streams of air in the middle atmosphere that are important for air travel and meteorology.

Adam Hart explores the archives of the Royal Society in London to reveal a story of how global observations of the atmospheric effects caused by the ejected smoke from Krakatoa unexpectedly revealed the presence of the jet streams.

Produced by Rory Galloway. First broadcast on Thursday 26 July 2018.