Ever on & on

How do we define greatness in science? I started pondering this question after responses started coming in to Nature Chemistry‘s “unscientific & arbitrary Twitter poll“, asking “Who is the greatest chemist of all time?” The results are now posted on The Skeptical Chymist, the Nature Chemistry blog.

My opening question was sparked by a particular name on the list: Fritz Haber.

Fritz Haber syntheszizes ammonia in the lab. Where's your PPE, Fritz?!? (Image from BASF)

Even if you’re not a chemist, you might have heard of Haber in a general chemistry course. A German chemist, Haber is most widely known for the reaction that bears his name, the Haber or Haber-Bosch process, the first method for synthesizing ammonia from nitrogen and hydrogen gases. It may seem trivial now, but at the time, chemists had been trying to do just that for over a century. Haber and collaborator Robert Le Riossignol found that under high pressure and high temperature, the gases would react to form ammonia. The formation of ammonia was still quite slow, but Haber and Le Riossignol subsequently discovered that the rare metal osmium accelerated the reaction.

Following a successful demonstration of the process, Carl Bosch and Alwin Mittasch, working for Germany’s largest chemical company, BASF, were tasked

with industrializing the process. Being a rare metal, osmium was expensive and its supply limited. Mittasch tried 4000 catalysts and found that a mixture of iron and metal oxides, a much cheaper and more abundant alternative, could be used. The first industrial unit fired up in September 1913, generating up to 5 tons of ammonia every day.

At this scale, ammonia could be readily converted to nitrates, which were (and still are) used in fertilizers and explosives. Prior to industrial production of ammonia, Germany’s primary source of nitrates was saltpeter mines in Chile, a supply expected to be depleted within 30 years. Moreover, supply from the mines was blocked by the British Royal Navy after the start of World War I in 1914. An oft-quoted claim (for which I can find no citation) is that at the start of WWI, Germany’s stockpile of saltpeter could only have supplied munitions for just over a year, and that without the Haber process, Germany would have been forced to end the war in 1916. Jerome Alexander, a chemist of the day, even suggested that “without the Haber process it is doubtful Germany would have started the war, for which she carefully prepared.”

Haber’s impact on the war front did not stop there. Haber was a fierce patriot, devoting his time, intellect, and force to Germany’s war effort, and he was appointed to the War Department for Raw Materials as head of chemistry. By numerous accounts, he lived by his credo, “In peace for mankind, in war for the fatherland!” Realizing that tear gas

From Le Miroir, 1915 (source unknown)

would be ineffectual on the frontlines, Haber recommended using chlorine gas to flush enemy soldiers out of the trenches. He committed to turning this idea to reality, even though it was in direct contravention to the Hague Conventions. He oversaw every aspect of the effort–manufacturing, testing, installation.

The first test on the frontlines came at the second Battle of Ypres, ushering in a new era of warfare. Over 150 tons of chlorine gas were released within 10 minutes in each of two deployments in two days. The result: 15,000 casualties with 5000 dead, including many German soldiers because gas masks did not reach the front prior to the attack.

Haber continued to develop chemical warfare agents and tactics. He was not dissuaded by the suicide of his wife, who considered chemical warfare barbaric (although it’s unclear how much Haber’s work contributed to her suicide).It seems Haber hoped that chemical warfare would bring a swift victory, and thereby an early end to the war. Instead, by the end of the war, both sides were using chemical weapons, contributing to more than 90,000 deaths and over 1 million casualties. Yet even after the war, Haber continued to oversee development and production of chemical agents.

Soldiers drill in their gas masks during WWI. Photographer, unknown. Image from State Library of Queensland.

Haber’s war contributions was at the center of the consternation surrounding the 1918 Nobel Prize in Chemistry (which was not announced until 1920). Here stood a man who months before had been labeled a war criminal (although the charges were dropped), now being lauded for his scientific prowess. The Prize was awarded for “the synthesis of ammonia from its elements“, and the committee highlighted the importance of this accomplishment to agriculture. There was no mention of the use of ammonia for making explosives or of Haber’s campaign for chemical warfare.

And this brings us back to the question: What makes scientists great? Do we consider primarily their greatest scientific contributions? The brilliance and creativity that brought them to the answer for a long-held question, a solution for a problem plaguing the field? Do we focus solely on how their science benefited society?

The boom of human population growth in the last half of the 20th century would have been unsustainable without the Haber process.

The staggering rise in world population over the second half of the twentieth century was supported in part by the Haber-Bosch process. By one estimate (illustrated in graph above), in 2008, almost half the world’s population was sustained by agriculture dependent on fertilizer made from Haber’s ammonia.

Man standing in field of grain, unidentified farm, Washington, ca. 1910. Photographer, Albert Henry. Part of Albert Henry Barnes Photograph Collection at Univ. of Washington Libraries

Sometimes there are alternative uses for scientific discoveries and unforseen consequences. From my readings, the motivation behind Haber’s desire to make ammonia from air remains unclear. Some imply that he pursued this work with the knowledge–and maybe even intention–that it would be used for war. Others are more generous, suggesting he did it to help mankind, and the work was assimilated by others for more nefarious purposes. Max Perutz wrote:

By a terrible irony of fate, it was his apparently most beneficent invention, the synthesis of ammonia, which has also harmed the wold immeasurably. Without it, Germany would have run out of explosives once its long-planned blitzkrieg against France failed. The war would have come to an early end and millions of young men would not have been slaughtered. In these circumstances, Lenin might never have got to Russia, Hitler might not have come to power, the Holocaust might not have happened, and European civilization from Gibraltar to the Urals might have been spared.

Some shell cases on the roadside in the front area, the contents of which have been despatched over into the German lines. Photographer, Tom Aitken. From the National Library of Scotland.

Nonetheless, we should not ignore the dark side of science and its practitioners. How should our perception of the morality of scientists’ actions affect the laud of their work or their standing as the greats of science? Setting aside Haber’s motivation for making ammonia, he had a very good idea of what he was promoting when he began developing toxic gases and delivery methods.

But what of the brilliant minds involved in the making of the atomic bomb? Do we more readily overlook the “sins” of scientists if, later in life, they expressed remorse over their contributions to death and destruction? Do we excuse culpability because we consider a cause just? Is it the level of involvement–whether a scientist was active, complicit, or simply stood by and did nothing–that affects our perspective?

Should we consider the inevitability of a discovery? Does it make a discovery less great–or the blame for negative impact less dire–if others were nipping at their heels? Perutz posited:

Haber’s synthesis of ammonia for fertilizer was an extremely important discovery, but unlike relativity, it did not tak a scientist of unique genius to conceive it; any number of talented chemists could, and no doubt would, have done the same work before very long.

I suspect the same would hold true for chemical warfare. If it hadn’t been Haber, it would have been someone else. And Allied forces responded with similar tactics in turn. Neither point dims Haber’s reputation as the father of chemical warfare, though.

Moving beyond the questionable and destructive work of the great scientists, what of some of the more eccentric ideas or less rigorous investigations of famous scientists? How do these alter our concept of greatness? Haber was one of many who spent years trying to extract gold from seawater.

Linus Pauling, one of the greats but not without his flaws. Photograph from the Smithsonian Institution Archives.

Or consider, as Neil Withers pointed out, Pauling’s promotion of vitamin C as a health remedy. As Perutz noted in an essay on the subject, “It seems tragic that this should have become one of Pauling’s major preoccupations for the last 25 years of his life and spoilt his great reputation as a chemist.” It is worth noting though that Perutz still considered Pauling the greatest chemist of the century, in spite of this failing. Others may feel that great scientists should not have such weaknesses, but I find it easier to pass over these more innocuous shortcomings. In my mind, such idiosyncrasies remind us that these legends were indeed human and, thus, flawed. They also provide cautionary tales of how even the brightest minds can fall into trap of searching for the answer they want to find, rather than the answer the data yield.

These questions are hardly new. But as we consider who the greatest individuals in our field might be, we would do well to contemplate not only their magnificent achievements but also the things that are sometimes hidden in their long shadows.

Additional References & Further Reading

Erisman, J. W.; Sutton, M. A.; Galloway, J.; Klimont, Z.; Winiwarter, W. “How a Century of Ammonia Synthesis Changed the World”. Nat. Geosci. 2008, 1: 636-630. PDF

Friedrich, B. “Fritz Haber”. Published in part in Angewandte Chemie (International Edition) 44, 3957 (2005) and 45, 4053 (2006). PDF

Gibson, A. “Chemical Warfare as Developed During the World War and Probable Future Development” (An Address at the Annual Graduate Fortnight of The New York Academy of Medicine, October 22, 1936). Bull. N. Y. Acad. Med. 1937, 13: 397-421. PDF

Perutz, M. F. “Friend or Foe of Mankind?” and “The Battle Over Vitamin C” “What Holds Molecules Together?” in I Wish I’d Made You Angry Earlier: Essays on Science, Scientists, and Humanity. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory Press, 2003.

“The Nobel Prize in Chemistry 1918”. Nobelprize.org. 22 Jan 2011 http://nobelprize.org/nobel_prizes/chemistry/laureates/1918/

*Where possible, I have listed primary sources of images in their captions. Original digitized versions may be accessed by clicking on the desired image.