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Caesar’s Last Breath

Caesar’s Last Breath: Decoding the Secrets of the Air Around Us

Sam Kean
Little, Brown
384 pp.
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The word “gas” appropriately comes from the Greek word for chaos (khaos): Within these intangible substances are trillions of tiny particles flying around at hundreds of miles an hour, forcefully slamming into each other, and ricocheting away in random directions. Yet, because gases are invisible to the naked eye, it is often easy to forget just how powerful and ubiquitous they are.

In Caesar’s Last Breath, Sam Kean describes how gases have played a lead role in many chapters of Earth’s history, from the beginning of the solar system to the current search for life on other planets. He interweaves scientific topics with tangential, but often humorous, stories about the people who helped to reveal important properties of gases. Who knew, for example, that Antoine-Laurent Lavoisier, who discovered the role that oxygen plays in combustion, once paid the modern-day equivalent of $280,000 for a portrait that included himself, his wife, and his chemistry equipment?

The book is split into three sections: the nuts and bolts of atmospheric composition; how gases have influenced humans; and, finally, how humans have influenced the atmosphere. Each chapter focuses on a different gas or a set of gases. In one, Kean recounts the “chemical cowboys” whose insatiable desire to find compounds for bigger and better explosives in the 1800s led to lab accidents, innocent deaths, and a vain attempt to repair a maimed reputation (of which the Nobel Prize is a result). In another, he shares the history of how nitrous oxide once wavered between the social classifications of medicine and party drug and describes its eventual role in slashing the suicide rate of patients about to undergo surgery.

Kean’s ability to explain with clear, vivid analogies provides diverse readers access to previously remote scientific concepts. For example, the strong triple bonds in the nitrogen molecules that make up 78% of Earth’s atmosphere render it inaccessible to the living things that require it to survive, he writes at one point, likening the experience to “dying of thirst in the middle of the ocean.” His detailed historical narratives are also interspersed with fun facts (e.g., the Haber-Bosch process, which creates the fertilizer that helps grow half of the world’s food, is responsible for an entire 1% of the world’s energy consumption), offering new perspectives to those already well versed in the science. Readers intimidated by chemical formulas and mathematical equations will be pleased by their minimal presence in this book.

Despite the book’s breadth—Kean covers more than 15 distinct topics—its stories are informative and well organized. He inarguably succeeds with his goal of “mak[ing] these invisible stories of gases visible.”

About the author

Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523, USA