Among his more important works are--_Loerebog i de enkelte Radicalers Chemi_ (1842); _Danmarks geognostiske Forhold_ (1835); _Om de Bornholmske Kulformationer_ (1836); _Dit myere Kridt i Danmark_ (1847); _Bidrag til Skildringen af Danmarks geographiske Forhold_ (1858). A list of his contributions to scientific periodicals, Danish, English and German, will be found in the _Catalogue of Scientific Papers_ published by the Royal Society of London. One of the most interesting and most recent is "On the Constitution of Sea Water at Different Depths and in Different Latitudes," in the _Proceedings of the Roy. Soc._ xii. (1862-1863). FORCHHAMMER, PETER WILHELM (1801-1894), German classical archaeologist, was born at Husum in Schleswig on the 23rd of October 1801. He was educated at the Lubeck gymnasium and the university of Kiel, with which he was connected for nearly 65 years. In 1830-1834 and 1838-1840 he travelled in Italy, Greece, Asia Minor and Egypt. In 1843 he was appointed professor of philology at Kiel and director of the archaeological museum founded by himself in co-operation with Otto Jahn. He died on the 8th of January 1894. Forchhammer was a democrat in the best sense of the word, and from 1871 to 1873 represented the progressive party of Schleswig-Holstein in the German Reichstag. His published works deal chiefly with topography and ancient mythology. His travels had convinced him that a full and comprehensive knowledge of classical antiquity could only be acquired by a thorough acquaintance with Greek and Roman monuments and works of art, and a detailed examination of the topographical and climatic conditions of the chief localities of the ancient world. These principles are illustrated in his _Hellenika. Griechenland. Im Neuen das Alte_ (1837), which contains his theory of the origin and explanation of the Greek myths, which he never abandoned, in spite of the attacks to which it was subjected. According to him, the myths arose from definite local (especially atmospheric and aquatic) phenomena, and represented the annually recurring processes of nature as the acts of gods and heroes; thus, in _Achill_ (1853), the Trojan War is the winter conflict of the elements in that district. Other similar short treatises are: _Die Grundung Roms_ (1868); _Daduchos_ (1875), on the language of the myths and mythical buildings; _Die Wanderungen der Inachostochter Io_ (1880); _Prolegomena zur Mythologie als Wissenschaft und Lexikon der Mythensprache_ (1891). Amongst his topographical works mention may be made of: _Topographie von Athen_ (1841); _Beschreibung der Ebene von Troja_ (1850), a commentary on a map of the locality executed by T.A. Spratt (see _Journal of the Royal Geographical Society_, xii., 1842); _Topographia Thebarum Heptapylarum_ (1854); _Erklarung der Ilias_ (1884), on the basis of the topographical and physical peculiarities of the plain of Troy. His _Demokratenbuchlein_ (1849), in the main a discussion of the