This is the Nature Pastcast, each month raiding Nature's archive and looking at key moments in science.

In this show, we travel back to the 1940s. Nature, Saturday, July 18th, 1942.

In 1942, it's one of the darkest periods of the Second World War for Britain.

The war with Germany is still ongoing, there's bombing, there's the blitz, great destruction.

My name's John Egar. I'm a historian of science at University College London,

and I'm fascinated by how science fitted in with the wider world in the 20th century.

Wars in general are very important for science because they call for new weapons,

they call for new defences, and scientists as experts are brought into that process. And in the 20th century, which was a century of global conflict, the scientists were

brought into that process like never before. And the Second World War, I think, is particularly

crucial because during the First World War, there were plenty of scientists were involved,

but many people felt that they weren't used effectively.

And there was a determination in the Second World War to change that.

And you can see that coming out in how nature covers the Second World War.

Page 65. Scientific Men in wartime.

From the outbreak of war in 1939, and indeed for a long time previously,

it was obvious that the knowledge possessed by scientific men and engineers

would be of decisive importance in the coming struggle.

It's fascinating reading nature in the Second World War.

One of the first things you notice when you see them on the shelves

is that the volumes for 1942, 1993,

are half the size of the pre-war and post-war volumes.

That's because people are doing war work.

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