Leonardo da Vinci - Kathleen Krull [1]
For Jane O’ Connor—K. K.
Acknowledgments
For help with research, the author thanks
Robert Burnham and Patricia Laughlin,
Patricia Daniels, Dr. Lawrence M. Principe,
Susan Cohen, Gary Brewer, Dr. Helen Foster James
and Bob James, Sheila Cole, Janet Pascal, Gery Greer,
and Bob Ruddick.
INTRODUCTION
“If I have seen further [than other people] it is by standing upon the shoulders of giants.”
—Isaac Newton, 1675
WHERE DO SCIENTISTS’ brilliant ideas and discoveries come from?
Well, nobody lives in a vacuum, and ideas don’t come out of nowhere. Even Isaac Newton (a giant of science if ever there was one) depended on what great thinkers before him had figured out in order to “see further,” to make discoveries of his own.
People hear the name Leonardo da Vinci, and they think “artistic genius of the Renaissance.” And sure, he created the Mona Lisa and The Last Supper, two of the world’s most famous paintings.
Yet for thirty years—the whole last half of his life—he spent most of his time doing research in fields ranging from astronomy to anatomy, zoology to geology, and botany to paleontology.
“Scientist” wasn’t even a word Leonardo would have known—people didn’t start using the term until the early nineteenth century. (He might have called himself a natural philosopher—someone who wants to make sense of the natural world.) But he would have known the Latin word scientia, which means “knowledge”—knowledge that explains the universe and the principles that make it work. Leonardo was very interested in scientia.
Yet, in books about scientists, Leonardo isn’t always included. Perhaps that’s because, in the history of science, Leonardo is like a bridge. He stands right between the medieval view of the world and the modern view based on observation and experimentation. He looks backward to a time when nature seemed illogical, magical. He looks ahead to a time when nature is viewed as operating by rules and laws that can be discovered.
Leonardo did indeed “see further” than anyone of his era. But whose “shoulders” did he stand on? And, in turn, did his work, his discoveries, inspire other scientists?
CHAPTER ONE
“So Many Things Unknown!”
EUROPE IN THE Middle Ages—first of all, there were no books. No printed books, that is. Just manuscripts in Latin, tediously copied by hand for the rich. Peasants had never seen one. Most people couldn’t read or write anyway.
There were no bathrooms. Hardly anyone knew what soap or underwear was. The poor ate with their fingers; utensils were for the rich. Most adults had no more than a few teeth in their heads.
Almost half of all children died before they were a year old. Women, on average, could expect to live only until age twenty-four. That’s because so many didn’t survive childbirth.
In the countryside, the poorest peasants lived in extreme poverty and filth, ten to twenty people to a damp hut. They slept on the floor, their farm animals—as well as rats—beside them. After a bad harvest, when a famine would sweep through, people starved to death.
In cities, streets served as toilets, and piles of excrement were left to mold until the next rain. Every few decades came a mysterious plague called the Black Death for the hideous black blisters it inflicted. The epidemic of 1348, which killed one out of every three people in Europe, was ascribed by many doctors to the rare placement in the sky of three planets.
Doctors varied wildly in training, and progress in medicine was sluggish. There were physicians with degrees from famous universities. Still, the books they studied had been written more than a thousand years earlier. Other “doctors” had little or no schooling; barbers sometimes performed surgery. And if a limb had to be amputated, pouring boiling oil onto the wound was the method used to stop bleeding. A urine flask was the universal symbol for physicians; they spent more time examining urine than anything else.
Doctors knew how to set broken bones. But the surefire cure for nosebleed? Pig manure.
Ten green lizards, cooked slowly in olive oil, were