Da Vinci Savings Time
Leonardo da Vinci did not invent the clock, but he did design a more accurate one. Clocks that showed hours and minutes had become increasingly accurate by the 15th century, even though the clock in the main square in Florence, Italy, where Leonardo lived much of his life, had only an hour hand—as it still does today. Think of the implications!
Leonardo's clock has two separate mechanisms: one for minutes and one for hours. Each was made up of elaborately connected weights, gears and harnesses. The clock also has a dial for keeping track of moon phases. Da Vinci's major innovation was to use springs rather than weights to operate his clock. He also included a description of some materials that would be used to make the clock – including diamonds and rocks.
But inventing a better mechanism to measure time seems only to have been a means to give Leonardo more of it. For he had much he needed to accomplish in his days on Earth.
Sleep: a Secret Weapon?
As a well-spent day brings happy sleep, so a life well used brings happy death.
It is rumored that Leonardo followed a weird sleep cycle: 20-minute naps every four hours! This may have been one of the secrets of why he was so productive—he had more awake time than the average person of his day (or ours!), whose sleep cycle without electric light might more closely follow the pattern of day and night.
We also know that da Vinci invented a night clock-candle to track what a sundial could not—perhaps so he could work through the night.