160 COSMOS. 



Germany to a considerable amount of literary dissension, 

 which, however, was of a very harmless nature. They pre- 

 sent a number of problems, which are by no means incapable 

 of solution, but which have been much neglected in recent 

 times, and only very imperfectly investigated both as regards 

 observation and experiment. The force of this magnetism 

 of rocks may be tested for the determination of the increase 

 of magnetic intensity by means of pendulum experiments 

 and by the deflection of the needle in broken off fragments of 

 hornblende and chloritic schists, serpentine, syenite, dolerite, 

 basalt, melaphyre and trachyte. We may in this manner 

 decide by a comparison of the specific gravity, by the rinsing 

 of finely pulverised masses, and by the application of the 

 microscope, whether the intensity of the polarity may not 

 depend in various ways upon the relative position, rather 

 than upon the quantity, of the granules of magnetic iron 

 and protoxide 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. 24 An accurate astronomical determi- 



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

 the year 1796, at the time that I fulfilled the duties of superintendent 

 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 

 Allgem. Jenaer Litteratur-Zeitung, Dec. 1796, No. 169, s. 1447, and 

 Mdrz, 1797, No. 38, s. 323 326; Gren's Neues Journal der Physik, 

 Ed. iv, 1797, s. 136 ; Annales de Chimie, 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 1816 (Beschreibung des Fichtelgelirges, Bd. i, s. 176), 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 chloritic and hornblende schists. 

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

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

 ascent to (Jhimboi-azo, groups of columnar masses of trachyte disturbed 

 thp motion of the needle at a distance of three feet. It struck me a-i n 

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



