ON THE MAGNETIC DISTURBANCES. 487 



of the complications produced by this presumed super- 

 position of phenomena, the separation of the indi- 

 vidual forces of which the fluctuations are the compound 

 result, and the assignment of the source and measure 

 of each, were viewed by that eminent geometrician as 

 "triumphs of science" which, though t( incontestably 

 very difficult of accomplishment," might not be unat- 

 tainable by perseverance in the course of inductive 

 investigation which had been so happily commenced. 

 (Eesultate, 1836, pp. 99100.) 



The scheme of the British colonial observatories, 

 adopted by the British Government on the joint recom- 

 mendation of the Royal Society and of the British Asso- 

 ciation for the advancement of science, was much more 

 comprehensive than that of the Grerman Association, inas- 

 much as it included the investigation of the laws of all the 

 magnetic variations, secular, periodical, and occasional, 

 sensible al* the surface of the globe ; and embraced as 

 distinct subjects of inquiry the phenomena of each of 

 the three magnetic elements, the declination, the incli- 

 nation, and the intensity of the magnetic force, the 

 whole phenomena, in fact, of the magnetic direction and 

 force, as they might be severally affected by the different 

 variations. The occasional disturbances (the subject of 

 this note) still preserved, however, a prominency in the 

 order in which the investigations were to be made; from 

 the circumstance, that the progressive and periodical 

 variations appeared to be so mixed up with the in- 

 fluences of the transient and occasional, that a know- 

 ledge of. the laws and relations of the latter, whereby 

 their effects might be eliminated, was deemed to be 

 indispensable towards a correct investigation and analysis 



