EXCERPT

INTRODUCTION

THE LAST BREATH

Indulge me in a modest experiment. For the next few seconds try paying close attention to the air escaping your body, as if this were your last living breath on earth. How much do you really know about this air? Feel your lungs deflate and sag inside your chest. What’s really going on inside there? Put your hand in front of your lips and feel how the gas escaping them has transformed inside you, growing warmer and more humid, perhaps acquiring an odor. What sort of alchemy caused that? And although your sense of touch isn’t nearly discriminating enough, imagine that you can feel the individual molecules of gas pinging your fingertips, impossibly tiny dumbbells, caroming off into the air around you. How many are there, and where do these molecules go?

Some don’t get far. As soon as you take another breath, they come rushing back into your lungs, like waves that fling themselves onto the shore before being retracted by the sea. Others stray a little farther and make a break for freedom in the next room before returning as well, miniature prodigal sons. Most simply join the anonymous masses of the atmosphere and begin to spread around the globe. But even then, perhaps months later, a few weary pilgrims will stagger back to you. You might be a very different person between your first and second encounters with these molecules, but the ghosts of breaths past continue to flit around you every second of every hour, confronting you with every single yesterday.

Of course, you’re not alone in experiencing this; the same thing happens to every other person on Earth. Moreover, your ghosts are almost certainly entangled with theirs, since they almost certainly inhaled and expelled and rebreathed a few of those very same molecules after you did—or even before you did. In fact, if you’re reading this in public, you’re inhaling the exhaust from everyone around you right now—secondhand breath. Your reaction to this will probably depend on the company you keep. Sometimes we enjoy this mingling of airs, as when lovers lean in and we feel their breath on our necks; sometimes we abhor it, as when the chatterbox next to us on the plane has eaten garlic for lunch. But short of breathing from a tank, we can’t escape the air of those around us. We recycle our neighbors’ breaths all the time, even distant neighbors’. Just as light from distant stars can sparkle our irises, the remnants of a stranger’s breath from Timbuktu might come wafting in on the next breeze.

Even more startling, our breaths entangle us with the historical past. Some of the molecules in your next breath might well be emissaries from 9/11 or the fall of the Berlin Wall, witnesses to World War I or the star-spangled banner over Fort McHenry. And if we extend our imagination far enough in space and time, we can conjure up some fascinating scenarios. For instance, is it possible that your next breath—this one, right here—might include some of the same air that Julius Caesar exhaled when he died?

TABLE OF CONTENTS

• Introduction: The Last Breath
• I. MAKING AIR: OUR FIRST FOUR ATMOSPHERES
  • Chapter One: Earth’s Early Air
  • Interlude: The Exploding Lake
  • Chapter Two: The Devil in the Air
  • Interlude: Welding a Dangerous Weapon
  • Chapter Three: The Curse and Blessing of Oxygen
  • Interlude: Hotter than the Dickens
• II. HARNESSING AIR: THE HUMAN RELATIONSHIP WITH AIR
  • Chapter Four: The Wonder-Working Gas of Delight
  • Interlude: Le Petomane
  • Chapter Five: Controlled Chaos
  • Interlude: Steeling Yourself for Tragedy
  • Chapter Six: Into the Blue
  • Interlude: Night Lights
• III. FRONTIERS: THE NEW HEAVENS
  • Chapter Seven: The Fallout of Fallout
  • Interlude: Albert Einstein and the People’s Fridge
  • Chapter Eight: Weather Wars
  • Interlude: Rumbles from Roswell
  • Chapter Nine: Putting on Alien Airs

EXTRAS

Extra Caesar’s Last Breath Notes

PRAISE

“Sam Kean has done it again—this time clearly and entertainingly explaining the science of the air around us. He is a gifted storyteller with a knack for finding the magic hidden in the everyday.”
—Daniel H. Pink, author of Drive

“The most fun to be had from nonfiction is a good science book, with a writer of craft who can capture both the excitement and the elegance of science, the incredible fact that this is really how it works. Sam Kean is such a writer and Caesar’s Last Breath is such a book. An enormous pleasure to read.”
—Mark Kurlansky, author of Paper and Salt

“Fascinating stories, so insightful, informative, and disarmingly written. It gave this astronaut a new respect for the air around us all, and made me delightfully more aware of each breath I take.”
—Col. Chris Hadfield, author of An Astronaut’s Guide to Life on Earth

“A witty book that turns the science of stuff we breathe into a delightful romp through history. Kean, an award-winning science writer…has done it again, using his free-wheeling style to translate hard scientific facts into lively stories.”
—Kirkus

“Riveting…Kean has a knack for distilling chemistry to its essential elements, using stories and humor…this is a dose of fresh air.”
—Library Journal

“Kean pumps chemical and historical trivia into this tale about air and the gases of which it is composed…lightweight and entertaining.”
—Publishers Weekly