Карл Вильгельм Ган: Зоолог и автор первой немецкой монографии о пауках

German zoologist

Carl Wilhelm Hahn (Lat. Carolus Guilielmus Hahn, 16 December 1786 – 7 November 1835) was a German zoologist and author of the first German monograph on spiders. C. W. Hahn was an all round natural scientist – not at all unusual for his time. Surprisingly, he seems to have been almost forgotten. Even the few biographical dates that have been published in secondary literature are not always correct as clarified by P. Sacher in his "attempt at a Biography".

Carl Wilhelm Christian Hahn was born in Weingartsgreuth, Upper Franconia, as the first son of Johann Michael Hahn (1734–1824), who was court and palace gardener on the estate of Baron von Seckendorff, later palace gardener for Count Friedrich von Pückler. He obeyed the general call to arms as early as 1813, and served as a quartermaster, and in 1816, received his honourable discharge. Afterwards, he lived with his parents in Fürth, and according to Hahn, made up his mind to devote his life to his predilection for natural history, an interest he had possessed since early childhood and which intensified during his studies in Erlangen. He commenced work on his first ornithological work, Birds from Asia, Africa, America and New Holland. When his "often promised and well earned position" failed to materialize, Hahn undertook what was for that time, in his field, a very unusual step and went freelance. From then on, he called himself a natural historian and occasionally also a scholar. On 24 February 1820, having in the meantime qualified as a Dr. Phil. at the University of Erlangen, he married Victoria Francisca Kaltdorff, née Schaefer. His wife, the widow of a doctor of medicine, was about five years older than he, and had three children by her previous marriage. She was at this time without means, but was expecting quite large inheritance from her maternal uncle before long. Their own child, Anna Friedericke, was born at the end of 1820 or 1821. Hahn is assumed to have been in close contact with the universally known natural scientist Jakob Sturm, and probably with his two sons. He named a spider species after Jakob: Araneus Sturmii, now Atea sturmi (Hahn, 1831). His relationship with Johann Georg Wagler must have been similarly close. He also named a spider species after him: Lÿcosa Waglerii, now Pardosa wagleri (Hahn, 1822). Nothing reliable is known about other contacts within the remarkably productive Nuremberg zoologist scene, nor does any proof exist that Hahn knew Franz von Paula (von) Schrank personally, a highly regarded natural scientist, to whom he dedicated the "Monograph on Spiders". The scientific value of Hahn's lifework in natural history varies. His ornithological work, for example, never had any discernible influence on this field. Hahn's work on the true bugs (Heteroptera), though, is just as important as his works on spiders (Araneae). One species of bug even carries his name: Lopus hahni Stål, 1860. He was also given this honour in the field of arachnology: Carl Ludwig Koch, who continued "Die Arachniden" after Hahn's death, called a genus after him in 1841 (Hahnia), on which later the name of the whole family was based – Hahniidae Bertkau, 1878. Hahn died in Nuremberg on 7 November 1835, "of a lung complaint in the prime of life".

Until the end of the 18th century, all studies of spiders, scorpions, and related forms were treated as part of the wider study of entomology, for these were described as wingless insects and included in one genus, the Aranea of Linnaeus, of perhaps 500 different species. Based on Walckenaer's "Fauna Parisienne" (1802) Latreille established the first set of genera for spiders in his work, which is marking the real beginning of arachnological systematics, and which was extended by Walckenaer into the important "Histoire naturelle des Insectes Aptères" (1837–1847). During the mid 19th century, the centre of activity shifted away from France to Germany. An important part of this shift was due to the 14 volume work of Hahn and C. L. Koch, "Die Arachniden" (1831–1848). In contrast to the French manuscripts with their terse descriptions and infrequent illustrations, the 2000 plus pages of beautifully coloured plates of this work captured the attention of zoologists everywhere. French arachnologist Simon was incited by the high number of species, described from Germany in "Die Arachniden", while from his native France almost nothing had been done. In particular, "Die Arachniden" was very influential in founding a German tradition of active interest in arachnology, which flourished for nearly a century. Its major shortcoming, as was realized later, was the lack of a natural scheme of classification, particularly above the family level.

"This person is indeed extremely foolish, but is incidentally polite, draws exceedingly well, has a beautiful hand, has much knowledge of natural history and botany, and is skilled in stuffing birds. However, because of his foolishness, he requires strict supervision. His other talents and capabilities make him worthy of some consideration. ", Count Pückler in 1805 to colonel of the infantry regiment, Erbach von Henneberg.