182 



of TTJ J 5 -th of the magnetic intensity is measured, and, at ocr 

 tain, epochs, observations are made at intervals of 2^ minutes, 

 and continued for twenty-four hours consecutively. A great 

 English astronomer and physicist has calculated* that the 

 mass of observations which are in progress will accumulate in 

 the course of three years to 1,958,000. Never before has so 

 noble and cheerful a spirit presided over the inquiry into the 

 quantitative relations of the laws of the phenomena of nature. 

 We are, therefore, justified in hoping that these laws, when 

 compared with those which govern the atmosphere and the 

 remoter regions of space, may, by degrees, lead us to a more 

 intimate acquaintance with the genetic conditions of magnetic 

 phenomena. As yet we can only boast of having opened a 

 greater number of paths which may possibly lead to an ex- 

 planation of this subject. In the physical science of terres- 



bd. xxxiii., s. 426.) In the magnetic association that was now formed 

 with G8ttingen for its center, simultaneous observations have been un- 

 dertaken four times a year since 1836, and continued uninterruptedly 

 for twenty-four hours. The periods, however, do not coincide with 

 those of the equinoxes and solstices, which I had proposed and followed 

 out in 1830. Up to this period, Great Britain, in possession of the most 

 extensive commerce and the largest navy in the world, had taken no 

 part in the movement which since 1828 had begun to yield important 

 results for the more fixed ground- work of terrestrial magnetism. I had 

 the good fortune, by a public appeal from Berlin, which I sent in April, 

 1836, to the Duke of Sussex, at that time President of the Royal So- 

 ciety (Lettre de M. de Humboldt a S.A.K. le Due de Sussex, sur lea 

 inoyens propres a perfectionner la connaissance du magnetisme terrestre 

 par 1'etablissement des stations magnetiques et d'observations corre- 

 ppondantes), to excite a friendly interest in the undertaking which it 

 had so long been the chief object of my wish to carry out. In my let- 

 ter to the Duke of Sussex 1 urged the establishment of permanent sta- 

 tions in Canada, St. Helena, the Cape of Good Hope, the Isle of France, 

 Ceylon, and New Holland, which five years previously I had advanced 

 as good positions. The Royal Society appointed a joint physical and 

 meteorological committee, which not only proposed to the government 

 the establishment of fixed magnetic observatories in both hemispheres, 

 but also the equipment of a naval expedition for magnetic observations 

 in the Antarctic Seas. It is needless to proclaim the obligations of 

 science in this matter to the great activity of Sir John Herschel, Sabine, 

 Airy, and Lloyd, as well as the powerful support that was afforded by 

 the British Association for the Advancement of Science at their meet- 

 ing held at Newcastle in 1838. In June, 1839, the Antarctic magnetic 

 expedition, under the command of Captain James Clark Ross, was fully 

 arranged ; and now, since its successful return, we reap the double 

 fruits of highly important geographical discoveries around the south 

 pole, and a series of simultaneous observations at eight or ten magnetic 

 stations. 



* See the article on Terrestrial Magnetism, in the Quartern F.yne* 

 1840, vol. Ixvi p 271-312. 



