TERRESTRIAL MAGNETISM. 155 



and protoxyd of iron intermixed in the mass. More im- 

 portant, however, in a cosmical point of view, is the question 

 which I long since suggested in reference to the Haidberg 

 mountain, whether there exist entire mountain ranges in 

 which opposite polarities are found to occur on opposite de- 

 clivities of the mass.* An accurate astronomical determin- 



* This question was made the subject of lively discussion when, in 

 the year 1796, at the time that I fulfilled the duties of superintend- 

 ent of the mining operations in the Fichtelgebirge, in Franconia, I dis- 

 covered the remarkable magnetic serpentine mountain (the Haidberg) 

 near Gefress, which had the property at some points of causing the 

 needle to be deflected at a distance of even 23 feet (Intelligenz-Blatt 

 der Allyem. Jenaer Litteratur-Zeituny, Dec., 1796, No. 169, s. 1447, 

 and Marz, 1797, No. 38, s. 323-326 ; Gren's Neues Journal der Physik y 

 bd. iv., 1797, s. 136-; Annales de C/iimie, t. xxii., p. 47). I had thought 

 that the magnetic axes of the mountain were diametrically opposed to 

 the terrestrial poles ; but according to the investigations of Bischoff 

 and Goldfuss, in 181Q (Beschreibtmg des Fichtelyebiryes, bd. i., s. 17ft), 

 it would appear that they discovered magnetic poles, which penetrated 

 through the Haidberg and presented opposite poles on the opposite 

 declivities of the mountain, while the directions of the axes were not 

 the same as I had given them. The Haidberg consists of dull green 

 serpentine, which partially merges into chloride and hornblende schists. 

 At the village of Voysaco, in the chain of the Andes of Pasto, we saw 

 the needle deflected by fragments of porphyritic clay, while on the 

 ascent to Chimborazo groups of columnar masses of trachyte disturbed 

 the motion of the needle at a distance of three feet. It struck me as a 

 very remarkable fact that I should have found in the black and red 

 obsidians of Quinche, north of Quito, as well as in the gray obsidian of 

 the Cerro de la Navajas of Mexico, large fragments with distinct poles. 

 The largo collective magnetic mountains in the Ural chain, as Blago- 

 dat, near Kuschwa, Wyssokaja Gora, at Nishne Tagilsk, and Katsch- 

 kanar, near Nishne Turinsk, have all broken forth from augitic or 

 rather uralitic porphyry. In the great magnetic mountain of Blago- 

 dat, which I investigated with Gustav Rose, in our Siberian expedi- 

 tion in 1829, the combined effect of the polarity of the individual parts 

 did not, indeed, appear to have produced any determined and recog- 

 nizable magnetic axes. In close vicinity tp one another lie irregular- 

 ly mixed opposite poles. A similar observation had previously been 

 made by Erman (Reise urn die jKrde, bd. i., s. 362). On the degree of 

 intensity of the polar force in serpentine, basaltic, and trachytic rock, 

 compared with the quantity of magnetic iron and protoxyd of iron, 

 intermixed with these rocks, as well as on the influence of the contact 

 of the air in developing polarity, which had already been maintained 

 by Gmelin and Gibbs, see the numerous and very admirable experi- 

 ments of Zaddach, in his Beobachtungen iiber die Marjnetische Polaritat 

 des Basaltes und der Trachytischen Gesteine, 1851, s. 56, 65-78, 95. A 

 comparison of many basaltic quarries, made with a view of ascertain- 

 ing the polarity of individual columns which have stood isolated for a 

 long period, and an examination of the sides of these columns which 

 have been recently brought in contact with the outer air in conse- 

 quence of the removal from individual masses of a certain depth of 



