Often cited as the archetypal “Renaissance man,” Leonardo came from an era in which the well-rounded individual, prolific and curious of mind, was highly valued.

In their book The Fourth Turning, Howe and Strauss identified four generational archetypes: Hero, Artist, Prophet, and Nomad. Each consists of people born in a roughly 20-year period. As each archetypal generation reaches the end of its 80-year lifespan, the cycle repeats.

Chinese New Year, like Passover, Rosh Hashanah and all Jewish holidays, pops up at various times each year within two months of the Gregorian calendar (January and February), because the Chinese calendar, like the Hebrew calendar, is based on the Metonic cycle, a lunisolar calendar that intercalates an extra month seven times in a 19-year cycle (as opposed to the Gregorian, with its months of varying lengths and its additional day every four years).

Once the existence and the length of the fraction of a day has been discovered, this difficulty can be corrected, as it is in our calendar, by intercalating a single day at regular intervals, but the discovery requires very precise methods of measurement, and throughout antiquity only approximate values for the fraction were known.

It’s a hoary old debate: how much do our genes define how we grow and learn, and how much is due to the environment? A new study by [Augustine] Kong and colleagues shows that parents’ genes, even those not passed on to children, have major effects on kids’ health and educational attainment.

Webster included [in the dictionary] new American words like “subsidize” and “caucus,” and left out hoary Britishisms like “fishefy.” John Quincy Adams, the future president, was shocked by the “local vulgarisms,” and doubted that Harvard, of which he was a trustee, would ever endorse such a radical “departure from the English language.”