Primo Levi. Credit: AP

A historical investigation has posthumously cleared Eligio Perucca, a physics professor at the Polytechnic University of Turin, of alleged anti-semitism towards Primo Levi.

Levi, an Italian chemist, writer and Auschwitz survivor, described in his book The Periodic Table the difficulties he had faced in persuading several professors in Turin to take him on as a doctoral candidate in 1940, because of the race laws that the Fascist regime imposed in Italy at that time. Perucca was later fingered as one of these professors in a Levi biography.

But Bart Kahr, a chemist at the University of Washington in Seattle, has looked into the claim and deduced that Perucca was not a fascist nor an anti-semite.

What's more, the investigation credits Perucca with a chemical discovery — of a certain type of optical activity, called optical rotary dispersion, of dyed chiral sodium chlorate crystals — in 1919 that was thought to have been discovered only in 1931.