220 BC

Events in 220 BC 1

• 220 BC The Method of Mechanical Theorems A secret letter to Eratosthenes — how he actually discovered his results In a letter to Eratosthenes, Archimedes revealed the secret heuristic method he used to discover (but not formally prove) his mathematical results: he imagined slicing geometric figures into infinitely thin strips and balancing them on a lever, using the law of the lever to deduce relationships between areas and volumes. This technique is essentially integral calculus. Archimedes did not consider it rigorous enough for formal proof — he used the method of exhaustion for that — but as a discovery tool, it was 1,800 years ahead of Newton. The work was lost for centuries and only rediscovered in 1906.