Review of The Alchemy of Air by Thomas Hager (Crown, 2008)

Nitrogen is vital to life, a key element for the growth of food.  It’s also key in the production of gunpowder.  It is all around us in the atmosphere, but it is only naturally converted from air into the soil through certain bacteria on the roots of legumes and by lightning.  That is why the fertility of soil gets depleted and crop rotation has been essential for maintaining yield.  Prior to the early twentieth century, the only other large-scale sources were a couple of nitrate rich areas - deposits in deserts or deposits of guano that were fought over and heavily depleted.  As the population rose towards the end of the nineteenth century there were concerns that there would be mass starvation as the world’s agricultural land reached peak food, which is estimated to be foodstuffs for 3-4 billion people.  The solution was the discovery of a method to fix nitrogen leading to the production of nitrogen-based fertiliser.  It was a process developed and driven by two Germans, Fritz Haber and Carl Bosch, aided by a massive team of scientists and technicians and the industrial might of BASF.  The scale of effort involved in cracking its industrial production made it the Manhattan project of its day.  It also had other knock-on consequences, keeping Germany in the First World War by boosting both food and explosive production.  The consequence of the discovery is an obesity crisis in many nations, proliferation of weapons, and massive nitrogen pollution of rivers and lakes.

After setting the scene and charting the natural sources of nitrogen and the wars fought over its harvesting, The Alchemy of Air tells the story of the fixing of nitrogen, primarily through plotting the careers of Haber and Bosch.  Both men were ambitious and determined, and their careers went up and down at different points, and both won Nobel prizes.  Haber, a Jew, was nationalistic and a somewhat confrontational and controversial character, having also invented gas warfare in the First World War, but ultimately became a victim of Hitler’s scientific culls.  Bosch was more reserved and private, but was a schemer and empire builder, helping to found and then lead IG Farben, the world’s largest chemical company.  He did try to confront Hitler’s regime but was eased to one side, dying an alcoholic.  Hager’s telling gets the balance between wider historical context of seeking natural sources of nitrogen, the science in its fixing, and the biographies of both men just right for a popular science history text.  Moreover, the narrative is interesting and engaging.  It does though slightly oversell itself - the story is not untold and Hager’s account is one of a number, and nor are Haber or Bosch as forgotten as he suggests.  Sure, they might not be household names in America, but they would be well known within the sciences and continental Europe.  Overall, a well-told tale of the development of the science and technology that keeps over 2 billion from starving to death.