FraSkidenstrædeTilHCØrstedInstitutet

stable into a professor’s residence. The first floor of this building came to house the Physics Collection while the floors above this became H. C. Oersted’s professorial residence. In the rebuilt, two- storied chemical laboratory in the court-yard H. C. Oersted, the chemist, in 1824 worked out the first method for producing free aluminium metal with aluminium chloride as an intermediate stage. In this century nothing was known as to the situation o f this laboratory. The forgotten building was pulled down in 1914, and it remained hidden in the past. It has now been identified in the painting shown on p. 101 and by means of a snapshot from 1914. Proof o f an extension to the laboratory between 1829 and 1860 is given, and a drawing of this as an “L ” is included. After 1860 extension from 1829 was pulled down, and the labo­ ratory building again came to have one wing only, as was the case when it was put up in 1823. As already mentioned it was pulled down in 1914 to make room for future university extensions. Oersted’s discovery of 1825 by which he showed the element alu­ minium can be produced as free metal, was not internationally published as was the case with his discovery of electromagnetism in 1820. His publication only appeared in Danish. See page 106. The first stage is expressed as AI 2 O 3 + 3 C + 3 CI 2 = 2 AICI 3 + 3CO at the temperature af incandescence.The next stage: Oersted reduced this anhydrous chloride with potassium as amalgam AlCLs + 3K = 3KC1 + Al. The mercury was distilled off. The apparatus is shown here. The latter together with the further development is thoroughly dealt with in this book. Wøhler paid a visit to Oersted in Copen­ hagen, and as Oersted had no time nor the money for research work, he suggested that Wøhler should continue his work on the understanding that the honour of the discovery remained with Oersted himself. Nevertheless Wøhler published the discovery in 1827 without mentioning Oersted’s name. When in this century aluminium became of such great importance all over the world, Dr. Fogh (in 1919 - foliowing Oersted’s description of his experi- ment —made a control experiment with a satisfactory result. A detailed account of this exists in German (by Professor Haas), and 231 9 Oersted’s discovery of aluminium.