of iron catalyst needed. In 1901 he built a small high-pressure apparatus along
the necessary principles but it blew up and he abandoned his research. Le
Chatelier was an expert metallurgist, well practised in high temperature
studies and the behaviour of gaseous mixtures and therefore ideally placed to
tackle the ammonia problem, but his findings were recorded in an obscure
French patent taken out under a foreign name and lost to the mainstream
thrust of research. Indeed, Haber was later to acknowledge that he only
became aware of Le Chatelier work after he had successfully, and independently, completed his own experiments.
16
This then was the’ state of play’ by 1905. Fixed nitrogen was available, but
expensively and in limited amounts. The ammonia synthesis was well
understood from a thermodynamic perspective but arguably less so from a
catalytic one. Many giants of chemistry had tackled the problem and failed,
giving rise to a prejudice that deterred further investigation. But as Ostwald
observed, all the ingredients for a solution were there and it became inevitable
that at some time a physical chemist would provide ‘very special equipment’
16
that would blend these ingredients and tease nitrogen and hydrogen to
combine in commercially viable amounts. But no-one it seemed, was about to
volunteer and take up this poisoned chalice.
However, the impasse was broken when Walther Nernst, along with
co-workers K. Jellinek and F. Jost, used his new ‘Heat Theorem’ to
re-examine the published results for various gaseous equilibria. They noticed
that only in the single case of Haber’s figures for the Margulies ammonia
investigation, were published experimental results seriously at odds with his
predictions. In particular, Haber’s choice for the percentage of ammonia
present in the equilibrium mixture at atmospheric pressure and 1020 °C (i.e.,
0.012%) was far too high for Nernst who subsequently wrote to Haber in the
Autumn of 1906 informing him of his concerns. Nernst was Germany’s
pre-eminent physical chemist and Haber—a freshly appointed professor—
was disturbed by his observations. The letter was a private communication—
although Nernst had already voiced some concerns about Haber’s figures in
his Silliman
17 Memorial Lecture at Yale
18
—but Haber realised that if the
issue were to go unchallenged then it had immense potential to damage his
hard-earned reputation. Consequently, he was forced back to address the
ammonia problem.
In his Nobel lecture on 02 June1 920,
16 Haber recalls that;
… in 1906… a new determination of the ammonia equilibrium became
necessary. In the course of his investigations… Nernst succeeded in finding an
approximate formula which permitted a prediction of the [position of
90
D. Sheppard
the necessary principles but it blew up and he abandoned his research. Le
Chatelier was an expert metallurgist, well practised in high temperature
studies and the behaviour of gaseous mixtures and therefore ideally placed to
tackle the ammonia problem, but his findings were recorded in an obscure
French patent taken out under a foreign name and lost to the mainstream
thrust of research. Indeed, Haber was later to acknowledge that he only
became aware of Le Chatelier work after he had successfully, and independently, completed his own experiments.
16
This then was the’ state of play’ by 1905. Fixed nitrogen was available, but
expensively and in limited amounts. The ammonia synthesis was well
understood from a thermodynamic perspective but arguably less so from a
catalytic one. Many giants of chemistry had tackled the problem and failed,
giving rise to a prejudice that deterred further investigation. But as Ostwald
observed, all the ingredients for a solution were there and it became inevitable
that at some time a physical chemist would provide ‘very special equipment’
16
that would blend these ingredients and tease nitrogen and hydrogen to
combine in commercially viable amounts. But no-one it seemed, was about to
volunteer and take up this poisoned chalice.
However, the impasse was broken when Walther Nernst, along with
co-workers K. Jellinek and F. Jost, used his new ‘Heat Theorem’ to
re-examine the published results for various gaseous equilibria. They noticed
that only in the single case of Haber’s figures for the Margulies ammonia
investigation, were published experimental results seriously at odds with his
predictions. In particular, Haber’s choice for the percentage of ammonia
present in the equilibrium mixture at atmospheric pressure and 1020 °C (i.e.,
0.012%) was far too high for Nernst who subsequently wrote to Haber in the
Autumn of 1906 informing him of his concerns. Nernst was Germany’s
pre-eminent physical chemist and Haber—a freshly appointed professor—
was disturbed by his observations. The letter was a private communication—
although Nernst had already voiced some concerns about Haber’s figures in
his Silliman
17 Memorial Lecture at Yale
18
—but Haber realised that if the
issue were to go unchallenged then it had immense potential to damage his
hard-earned reputation. Consequently, he was forced back to address the
ammonia problem.
In his Nobel lecture on 02 June1 920,
16 Haber recalls that;
… in 1906… a new determination of the ammonia equilibrium became
necessary. In the course of his investigations… Nernst succeeded in finding an
approximate formula which permitted a prediction of the [position of
90
D. Sheppard