Today is the anniversary of the catastrophic eruption of Mount Vesuvius in A.D. 79 and the death of Pliny the Elder (born A.D. 23) in that event. The eruption, which followed several years of precursor ground movements, buried the cities of Pompeii and Herculaneum and is thought to have killed as many as 15,000 people. Subsequent major eruptions occurred in 1631, 1906, and 1944, the last just after the Allies had taken the city of Naples in World War II. Pliny the Elder is remembered primarily for his "Natural History," a comprehensive compendium of ancient knowledge of the natural world....