Prof. A. G. Hbghom — Life of Prof . A. E. Tornebohm. 51 



collection of four thousand slides, all made by himself. The grinding 

 and preparation of these slides was for him a daily gymnastic exercise, 

 which he did not like to neglect. It gave him great pleasure to 

 demonstrate to his colleagues new slides showing features of interest. 



Petrography was for him, however, more or less an incidental 

 occupation or else a means to an end in his profound researches into 

 Archaean geology. Apart from a series of smaller memoirs dealing with 

 the Archaean, Tornebohm published (1882) his monumental "Map of the 

 Ore-bearing Archaean in Middle Sweden " [Hellersa Sveriges Bergslag), 

 on the scale 1 : 250.000. The views set forth by Tornebohm in the 

 text accompanying this map as to the genesis of the Archaean rocks 

 and oi'es may be, in essential parts, antiquated ; but even when 

 regarded from the present standpoint of science, the map promises to 

 maintain its position for a long time as a most important primary source 

 of knowledge in regard to this exceedingly interesting Archaean district. 

 In addition Tornebohm made several ore-fields, included in this same 

 district, as Dannemora, Norberg, Persberg, and Falun, the subjects of 

 more detailed individual treatment, and he also described other mining 

 districts situated elsewhere in the great North European Archaean. 

 Among these may be mentioned the copper-mine district of Atvidaberg- 

 Bersbo, the renowned iron mountain Taberg, south of Lake Vettern, 

 and the Pitkaranta mines in Finland. 



Having accomplished the great map of Middle Sweden, Tornebohm 

 resumed his researches in the mountain range. During the ten years 

 that had passed away since he had published his first memoirs about 

 the geology of the highlands, the knowledge of the stratigraphy of 

 the district had but slightly advanced ; Tornebohm, however, was 

 fully aware that difficulties met his old interpretation, and that 

 a review of the whole evidence and a correlation of the Swedish and 

 Norwegian parts of the mountain range were necessary. Hardly, 

 however, could he have imagined that he would spend so much as 

 thirteen summers of laborious surveying before he could reach a 

 satisfactory theory of the tectonics ! 



"With admirable perseverance Tornebohm roamed through the 

 barren highlands in all directions, often returning to critical localities, 

 where new suggestions led him to reconsider his old ideas and working 

 hypotheses. It has been told that sometimes his assistants ran away 

 from him because they could not endure the fatigues or follow him 

 when with his great strides he rambled over the mountains. 

 Tornebohm needed but a slight equipment for his personal comfort. 

 Some handfuls of raisins and almonds were often his provisions for 

 a hard working day in the field. The desolateness of the country, 

 want of topographic maps, absence of fossils, sudden change in the 

 facies of the rock -groups, and varying stages in their metamorphism 

 combined to render geological surveying exceedingly difficult. At the 

 present day, thanks to the pioneer work of Tornebohm and to all the 

 added advantages of good topographic maps and developed means of 

 intercourse, students of a younger generation can easily appreciate 

 the main features of the geology, and they can hardly imagine the 

 difficulties which met the first explorations in these mountain ranges. 



This is not the place for a detailed account of the development of 



