Who knew a book about fertilizer could be so interesting?

After reading and enjoying Hager’s Demon Under the Microscope, I was curious about his other work.  The Alchemy of Air is about how we made the earth sustain more than 4 billion people by taking nitrogen out of the air and turning it into fertilizer.

At the turn of the 20th century, mass starvation was a real threat–the earth simply couldn’t yield enough food to keep up with the growing human population.  So chemists are tasked with solving this very, very big problem.  Two chemists in particular, Fritz Haber and Carl Bosch, discover a way to take nitrogen from the air, creating fertilizer.  The Haber-Bosch process, a result of years of trial and error, manufactures synthetic nitrogen fertilizer by turning atmospheric nitrogen into a form that can be used by plant life.  And now we humans are eating bread that has almost literally been made out of air.

Unfortunately, nitrogen is also used for explosives, and Haber and Bosch’s discoveries fueled the German war machine(s) of WWI and II.  Both Haber and Bosch were brilliant scientists but flawed men, and Hager traces their scientific experiments, developments on the global stage, and their personal triumphs and failures in four or five parallel story arcs.  He does this pretty successfully, but the many plots do get a little unwieldy in this book, and Hager sometimes gets bogged down in details in a way that he didn’t in Demon Under the Microscope.

This is a fascinating book–I knew nothing about nitrogen!–although it wasn’t the page turner I’d hoped it would be.  It’s a story that more people should know, especially given the ramifications of their discovery even today, like nitrogen pollution.