Leif Tronstad - minneartikkel i NATURE - juli 1945

P rofessorene E. K. Rideal og U. R. Evans skrev denne minneartiklen i NATURE, vol. 156, page 74, July 21, 1945:

  T he death of L. H. L. Tronstad on active service in Norway, while leading a daring operation in March 1945, has derived his country of one of its most outstanding men of science, and his collaborators in all parts of the world of a valued friend.

  L eif Hans Larsen Tronstad was born in 1903 at Baerum, near Oslo; his father, a farmer, died the same year. He studied chemistry in the Oslo Technical School and the Norwegian Technical University at Trondheim, obtaining brilliant successes despite the fact that he was at the same time working as a teacher and in support of his widowed mother and sister. His first important research was carried out at Berlin, during 1928-29 in Prof. Freundlich's laboratory. A qualitative method of detecting thin oxide films on metals, based on changes in the ellipticity of polarized light, had already been worked out by Freundlich, Patscheke and Zocher. Tronstad succeeded in developing the method to give quantitative measurements of thickness, and showed that, when iron was made passive by anodic treatment, the film thickness increased, while during cathodic activation the thickness diminished. This work not only supplied valuable information as to the cause of passivity, but also suggested a new method of ascertaining the thickness of invisible films, and the nature of the film substance.

  A fter further work on films resulting from electrochemical treatment carried out in Prof. Benedick's laboratory at Metallografiska Institutet, Stockholm, for which he received his doctorate at Trondheim, Tronstad proceeded in 1931 to the University of Cambridge. There he improved the method further, testing its accuracy by the study of monolayers of fatty acids, the thickness of which could be measured in other ways; part of this work was carried out in collaboration with C. G. V. Feachem.

  L ater Tronstad returned to Norway and was elected in 1934 to a temporary professorship in technical inorganic chemistry at the Norges Tekniske Høgskole; this chair was made permanent in 1936. He was one of the youngest professors in the country, popular alike with students and colleagues, and enjoyed the reputation of being a first-class teacher. At this stage he was joined by A. B. Winterbottom, and the polarized light method of studying films on metals was developed further. Although not well known to-day, its value is likely to become increasingly appreciated as time passes, especially as it can be employed for just that range of thickness where alternative methods are least useful. Moreover, the method can be used for the continuous study of a film in situ during its growth in almost any environment.

  T ronstad's interests were by no means confined to the study of films. He played a leading part in the organization of the Rjukan hydrogen plant of Norsk Hydro, for the large-scale separation of heavy water, large quantities of which were supplied for scientific research in Great Britain. Determinations of the physical constants of several deuterium derivatives were made by Tronstad and his associates at Trondheim and Rjukan. Tronstad's elctrochemical knowledge was of the greatest value to the Norwegian industries, especially those connected with steel, ferro-alloys, nitrogen, refractories and aluminium; he also carried out recearches on the effect of minor elements on the corrosion of aluminium and iron. His published scientific papers number about sixty.

  T ronstad was greatly attached to Great Britain, where he had many friends. His modesty, sincerity and cheerful good-humour were appreciated by all who met him. He had numerous interests outside science; for example, he was a fine athlete, being in his student days a member of the relay team which set up a Norwegian record for the 4 x 400 metres distance; he was also a lover of natural beauty, and took pride in Norwegian country folk and customs.

  D uring the War Tronstad was engaged in daring and dangerous work for his country, which led on the eve of victory, to his death in action. Details of his many-sided war activities must not be given, but it may perhaps be stated that the results achieved, which demanded the highest courage, organizing capacity and scientific skill, contributed directly to the speedy victory of the Allied Nations, besides saving the region which came to be known as "Southern England" from an even longer and more severe ordeal than it actually endured. He received the Order of the British Empire for his outstanding services.

  W e would like to thank Mr. A. B. Winterbottom and Capt. J. H. Reimers, as well as the Royal Norwegian Government Information Office, for kind assistance on many points.

E. K. Rideal,  U. R. Evans