I was interested to read the letter from Milton Orchin and William Jensen (C&EN, May 29, page 2), which commented on the review of "Master Mind: The Rise & Fall of Fritz Haber, the Nobel Laureate Who Launched the Age of Chemical Warfare" (C&EN, Feb. 6, page 29).
There is no doubt that Wilhelm Ostwald was the first to develop ammonia oxidation for industrial use from 1900 and was awarded French, British, and U.S. patents in 1902, well before BASF built the first ammonia plant based on Haber's process. Ostwald's work was based on Charles F. Kuhlmann's discovery that platinum oxidized ammonia to nitric acid and, for this reason, his German patent application was not allowed.
Practically, however, Ostwald's process used more platinum than was economical, and the process was improved in Germany, first by K. Kaiser and then Adolph Frank and Nikodem Caro. Kaiser was awarded U.S. and British patents while Frank and Caro were awarded a German patent. The Frank and Caro process is reported to have been used by BASF during World War I.
Having read Daniel Charles' book, there is no suggestion that Haber developed the nitric acid process but only that he recognized that the process could replace Chile saltpeter used at that time.
Batheaston, Bath, England