Royal Danish Academy of Sciences and Letters

Bohr returned to Copenhagen in 1945. He continued to do some research, but much of his time was now taken up by administrative work. The institute was being expanded, and new equipment was being installed. Plans had to be made concerning the lines of research that would be pursued at the expanded institute. He had other administrative duties as well. He had been president of the Royal Danish Academy of Sciences and Letters since 1939, and by now he was very much a celebrity, one of the best-known people in Denmark. The king and queen of Denmark, cabinet ministers, and foreign ambassadors all came to his home for dinner. And of course he also continued to have numerous visits by physicists. 

C. S. Jacobsen, in Sixteen Research Reports by the Niels Bohr Fellows of the Royal Danish Academy of Sciences and Letters, Matematisk-fysiske Med-delelser 41, Copenhagen, 1985. 

Conference on Petroleum Phase Behaviour and Fouling, Copenhagen, Denmark, Aug 27—31, 2000 AIChE, Royal Danish Academy of Sciences and Letters, University of Denmark. 

Ballhausen became a member of the Royal Danish Academy of Sciences and Letters in 1965. One function of the Academy which is exceptional is that it elects the members of the board of the Carlsberg Foundation. In 1972-1996, Ballhausen was a member of this board, and of the boards of the Carlsberg Laboratory and the Foundation s Institute of Biology. 

At DTU, he founded and directed the Center for Microbial Biotechnology. Prof. Nielsen has published more than 350 research papers and coauthored more than 40 books, and he is inventor of more than 50 patents. He has founded several companies that have raised more than 20 mUhon in venture capital. He has received numerous Danish and international awards and is member of the Academy of Technical Sciences (Denmark), the National Academy of Engineering (USA), the Royal Danish Academy of Science and Letters, the American Institute for Medical and Biological Engineering and the Royal Swedish Academy of Engineering Sciences. 

The solid work Bohr took up, in February 1905, when he was nineteen years old, was a problem in experimental physics. Each year the Royal Danish Academy of Sciences and Letters announced problems for study against a two-year deadline, after which the academy awarded gold and silver medals for successful papers. In 1905 the physics problem was to determine the surface tension of a number of liquids by measuring the waves produced in those liquids when they were allowed to run out through a hole (the braided cascade of a garden hose demonstrates such waves). The method had been proposed by the British Nobelist John William Strutt, Lord Rayleigh, but no one had yet tried it out. Bohr and one other contestant accepted the challenge. 

In this essay I examine how the periodic system or table was introduced in Denmark in the late nineteenth century, how it was used in chemical textbooks, and the way it was developed by a few of the country s scientists. Danish chemists had in the period an international orientation, which helped them in getting acquainted with Mendeleev s system and appreciating its strength. The main reason they felt the system to be attractive was its predictive force, especially its prediction of new elements and ability to accommodate new chemical knowledge. I pay particular attention to the work of Hans Peter Jorgen Julius Thomsen (1826-1909), which is an important example of neo-Proutean attempts to understand the periodic system in terms of internally structured atoms. Moreover, I direct attention to Mendeleev s connection to Danish science by way of his membership in the Royal Danish Academy of Sciences and Letters. 

Julius Thomsen, Classifications des Corps Simples, Royal Danish Academy of Sciences and Letters, Oversigt (1895) 132-136. The paper also appeared in German, in Zeitschrift fur anorganische Chemie 9 (1895) 190-193, and was translated into English in Chemical News 71 (1895) 89-91. 

To return to Thomsen, in a memoir of 1894 published by the Royal Danish Academy of Sciences, he offered a detailed examination of the atomic weights and their significance. His purpose was to establish that they, if only properly interpreted, revealed that the so-called atoms of our elements have evolved out of combination of particles of a common basic substance. He did not on this occasion discuss the relation to the periodic system, but this is what he did the following year, in a paper in which he proposed a new classification of the elements (Figure 8.1). From a formal point of view, Thomsen s innovation was merely to reverse periods and groups, which was not entirely original since versions of this kind had been proposed earlier, first by Thomas Bayley in 1882 and again by Carnelley in 1886. ° However, in 1894 Thomsen was unaware of these two systems, such as he stated in a letter to the American chemist Francis Venable (1856-1934), who in a book of 1896 described Thomsen s system in some detail. ... 

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