Neudrucke von Schriften und Karten über Meteorologie und Erdmagnetismus

Abstract

DR. HELLMANN is so well known by his laborious researches in matters relating to the history of early scientific documents and instruments, and by the very valuable bibliographical knowledge which he brings to bear upon the various publications of this nature, that it is unnecessary to say more than that the present volumes exhibit the same painstaking labour as those which have preceded them. The first contains fac-simile copies of some of the earliest papers on terrestrial magnetism and the mariner's compass; each document is very scarce, and only accessible with difficulty, and must be con sidered as a literary rarity. Among them is a letter from Pierre de Maricourt, dated August 12, 1269, which is the earliest known treatise on magnetism in Europe. The principal point in the paper is the distinction of the two poles of the magnet, and of their opposite attraction. A paper by F. Falero (Sevilla, 1535) contains the first published instructions for determining the magnetic declination, although its existence was discovered by Columbus in 1492. A letter by G. Hartmann, dated March 4, 1544, gives an account of his discovery of the magnetic dip and the first determination of the declination on the mainland. This document was buried in the archives at Königsberg until 1831, so that the discovery of the magnetic dip is generally attributed to R. Norman, who determined it for London in 1576. In a letter from G. Mercator to the Bishop of Arras, which was discovered during the present century in the library at Göttingen, the first mention is made of the earth pos sessing a magnetic pole. There are various other papers which we cannot refer to here, all of which are of great interest and value in throwing light upon the earliest development of the subject. The second volume con tains a reproduction of the first fundamental papers relating to atmospheric electricity. The electrical nature of thunderstorms was suspected early in the eighteenth century by Hauksbee and other Englishmen, but Prof. J. H. Winkler, of Leipzig, first clearly demonstrated the analogy between them and the electric spark in 1746; the experimental proof was proposed by B. Franklin in 1749, and first carried out, near Paris, by Dalibard on May 10, 1752.