Nicholson’s Aereometer

 ‘A fox knows many things, but a hedgehog knows one big thing.’ In 1953, the philosopher Isaiah Berlin drew on this cryptic and mysterious sentence, by the Greek poet Archilochus, to distinguish between the conceptions of history in Russian literature. It’s fun to ask who are chemistry’s hedgehogs and who the foxes? One person to classify might be the hugely influential but largely forgotten figure of William Nicholson, the discoverer of electrolysis.