g% Singular Magnttic Mounfain, 



it ftands alone, and pKfcnts to our knowledge a very extended image of the dimenfions 

 of magnetic fpheres. It is among the Alps of Sweden and Norway, thofe northern regions 

 which nature has enriched with an enormous depofit of iron lefs oxided than in our country, 

 that we were entitled to expert fimilar phenomena. 



I haften to communicate to you a difcovery I made in the month of November, and 

 which appears to me of confiderablc importance in the progrefs of geology. You are ac- 

 quainted. Sir, with the laws and the harmony which I have obferved in the direftion and 

 inclination of the ptunitive ftrata, from the banks of the Mediterranean to thofe of the 

 Baltic Sea. You have even condcfcendcd, jointly with our friend Dolomieu, to exprefs an 

 interefl with regard to this laborious undertaking; which, in more (kilful hands than mine, 

 would, I am well alTured, throw great light on the conflruftion of the globe. I traverfed 

 the chain of mountains of the High Palatinate and the margraviate of Bayreuth •, and I found, 

 in the bottom of the Fichtelgebirge, between Munichberg and Goldcronach, an jfolated hill, 

 which rifes to the elevation of fifty toifcs above the furrounding plain. Its height above the 

 level of the fea may be eftimated at two hundred and eighty, or three hundred, toifes. This 

 hill extends in length from weft to eaft, and forms a pyramid extremely obtufe. The rocks 

 which crown the fummit or ridge are compofed of ferpentinc of confiderable purity, 

 which, by its colour and foliated fracSure, approaches in various parts to the chlorithfchiefcr 

 of Werner (/chylous chlorite J. This ferpentine is divided into ftrata rather diftinft, of 

 wJiich the inclination to the north-wed: prefents an angle between 60 and 65 degrees. It 

 repofes on a foliated granite, mixed with hornblende ; a mixture which we diftinguifii by 

 the name of fyenite. I approached this ferpentine with the compafs, in order to determine 

 more accurately the angle it formed with the meridian. The magnetic needle was in a 

 (late of continual agitation. I advanced two fteps farther, and beheld that the north 

 pole was entirely turned to the fouth. I called two friends, MclTrs. Godeking and Kil- 

 linger, who aflifted me in my geological purfuits ; and we were alike penetrated with that 

 joy which the contemplation of interefting phenomena produces in the minds of thinking 

 men. I fhall not detain your attention by a full recital of our obfervations ; but fhall 

 merely prefent the rcfults, to which I may hereafter make additions, if my occupations 

 fhould not lead me from this part of Germany. 



The a£lion of this mountain of ferpentine upon the magnet (hews itfelf in a very curious 

 manner. The uncovered rocks which are fcen on the northern flope, and thofe on the 

 declivity towards the fouth, have poles direftly oppofite. The former exhibit only fouth 

 poles, and the latter north poles. The whole mafs of foliated ferpentine docs not therefore 

 poflefs a fingle raagnetieal axis, but prefents an infinity of different axes perfcflly parallel to 

 each other. This parallelifm aifo agrees with the magnetic axis of the globe, though the 

 poles of the ferpentinc are inverted ; fo that the northern pola of the hill is oppofed to the 

 fouth pole of the earth. The eaft and weftern flopfs prefent what in the theory of mag- 

 netifm would be called points of indifference. The magnet does not at this part appear 

 to be in any rcfpect alTefted, though the fubftance of the rock differs in no external cha- 

 rader from the other parts. It is the fame on the fouth fide of the fummit *. I have ob- 

 ferved not only that the magnetic axes are not difpofed in the fame horizontal p^ane ; but I 



* I fufpcft an error of the co^yift, as the words "II en eft dc mOme du cote meiiJional de la fommiti" 

 contfjdift the gcacral dclcription immediately preceding. N. 



have 



