46 Baron Humboldt on advancing the Knowledge 



church. This undertaking cannot be mentioned without re- 

 calling the fact, that, according to the Penthsaoyaiii, a me- 

 dical natural history composed under the Soung dynasty, 

 nearly four hundred years before Christopher Columbus and 

 the natives of Europe had the least idea of magnetic declina- 

 tion, the Chinese suspended the needle by means of a thread, 

 to allow it perfect freedom of motion ; and that they knew that 

 when thus suspended, according to the method of Coulomb, 

 (as in the Jesuit Lana's apparatus in the seventeenth century,) 

 the needle declined to the south-east, and never rested at the 

 true south point. Since the return of M. Fuss, M. Kowanko, 

 a young officer of mines, whom I had the pleasure to meet 

 in the Oural, continues the observations of horary declination, 

 corresponding to those of Germany, St. Petersburgh, Cazan, 

 and Nicolajeff in the Crimea, where Admiral Greigh has esta- 

 blished one of Gambey's compasses, the care of which is con- 

 fided to the director of the Observatory, Mr. Knorre. I have 

 also obtained the establishment of a magnetic apparatus at the 

 depth of thirty-five fathoms in an adit in the mines of Freiberg 

 in Saxony, where Mr. Reich to whom we are indebted for his 

 valuable labours upon the mean temperature of the earth at dif- 

 ferent depths, is assiduously engaged in making observations at 

 regulated intervals. M. Boussingault, who neglects nothing 

 which is calculated to advance the progress of the physics of the 

 earth, has sent us from South America observations of horary 

 declination made at Marmato, in the province of Antioquia, in 

 north lat. 5° 27', in a place where the declination is eastern, 

 as at Cazan and Barnaoul in Asia ; while on the north-western 

 coasts of the new continent, at Sitka in the Russian settle- 

 ments, Baron von Wrangel, also provided with one of Gam- 

 bey's compasses, has taken part in the simultaneous observa- 

 tions made at the time of the solstices and equinoxes. A Spanish 

 admiral, M. de Laborde, having been informed of a request 

 that I had made to the Patriotic Society of the Havannah, had 

 the kindness, unsolicited, to desire me to send him instruments 

 proper for determining with precision the inclination, the ab- 

 solute declination, and the horary variation of declination and 

 intensity of the magnetic forces. The valuable instruments 

 desired, exactly similar to those in the possession oftheObser- 

 vatoryof Paris, arrived in safety in the island of Cuba; but the 

 alteration in the maritime command at the Havannah, and other 

 local circumstances, have hitherto prevented the employment 

 of them, and the establishment of a magnetic station under 

 the tropic of Cancer. The same has also occurred up to the 

 present time with regard to one of Gambey's compasses which 

 M. Arago had caused to be erected, at his own expense, to 



