The Bombe is the famous machine. What almost nobody knows is that for three years it could not have coped with naval Enigma on its own, and the thing that made it possible was a stack of perforated paper sheets, a light, and a statistical method Turing invented that has…

Subrahmanyan Chandrasekhar was born in Lahore on 19 October 1910. In the summer of 1930, aged nineteen, he sailed from Madras to England to begin research at Cambridge, and he spent the voyage doing a calculation. The result was that a dead star cannot be arbitrarily heavy. Above a certain…

Search for almost any famous scientist and an image comes back immediately, confidently labelled, reproduced in textbooks and on stamps and in slide decks. For a surprising number of them the picture is an invention, a guess, or a portrait of somebody else entirely. The errors are not random either.…

Open the Principia expecting equations and you will not find them. There are no derivatives, no integral signs, and almost no algebra. What you find is diagrams, triangles, ratios of line segments and propositions that read like Euclid. This is odd, because Newton had invented calculus around 1665 and 1666,…

On the morning of 16 October 1843, William Rowan Hamilton walked along the towpath of the Royal Canal in Dublin with his wife, on his way to a meeting of the Royal Irish Academy. He had been stuck on the same problem for more than ten years. At Broom Bridge…

Until the autumn of 1846, surgery was something done to a conscious person who had to be held down. That single fact organised the whole discipline. Operations were chosen for what could be finished in seconds, not for what would help the patient most. Robert Liston in London could take…

On 14 October 1947, over the Mojave Desert, Chuck Yeager took a rocket plane to Mach 1.06 and became the first person confirmed to have flown faster than sound in level flight. Bullets had been doing it since the 1880s. The tip of a stockman’s whip does it every time…

Latitude is given to you. The equator is where the Earth’s rotation puts it and the poles are where the axis comes out, so nobody has ever had to negotiate about latitude. Longitude has no such anchor. Every line from pole to pole is exactly like every other one, so…

You can picture Newton. You can picture Boyle, Wren, Halley, Pepys, Leibniz and Huygens, because they were all painted and the paintings hang in institutions that look after them. Robert Hooke, who was Curator of Experiments and then Secretary of the Royal Society, who published Micrographia, who worked out the…

In 1699 a fifty two year old widow sold most of her paintings, borrowed money, obtained a small grant from the city of Amsterdam, and sailed to Surinam with her younger daughter to study insects. She had no institution behind her, no patron paying for the voyage and no husband…