Malus’s rays

Serendipity is much misunderstood. It is sometimes equated with a lucky accident, a discovery that might have been made by almost anyone but for the vagaries of chance, a bit like winning the lottery. The reality is rather different. Serendipitous discoveries are made by individuals deeply steeped in closely related science who not only spot a discrepancy, but follow the observation relentlessly to establish its reality.

Etienne-Louis Malus’ discovery of the polarisation of light is a good example. Malus was born in Paris, France, into a well-connected family. An excellent student, he won a scholarship to the Military Engineering School at Mézieres where Charles Augustin Coulomb had studied. Unfortunately, the French Revolution closed the school, leading Malus to volunteer for the army where he built earthworks in Dunkerque. Malus so impressed his superiors that they seconded him to the recently founded École Polytechnique in Paris.