Royal Society. 137 



President. — The Marquis of Northampton Treasurer. — John 



William Lubbock, Esq., M.A., V.P. — Secretaries Peter Mark 



Roget, M.D. ; Samuel Hunter Christie, Esq., M.A. — Foreign 

 Secretary. — William Henry Smyth, Capt. E,.N. — Other Members of 

 the Council.— R.W.B.. the Duke of Sussex, K.G., V.P. ; Francis 

 Baily, Esq., V.P. ; John George Children, Esq., V.P. ; John Fre- 

 deric Daniell, Esq. ; C. G. B. Daubeny, M.D. ; Thomas Galloway, 

 Esq., M.A. ; Thomas Graham, Esq.; Sir John F. W. Herscliel, 

 Bart., M.A., V.P. ; Francis Kiernan, Esq.; George Rennie, Esq.; 

 John Forbes Royle, M.D., V.P. ; Rev. Adam Sedgwick, M.A.; 

 Robert Bentlev Todd, M.D. ; Charles Wheatstone, Esq. ; Rev. 

 William Whewell, M.A. ; Rev. Robert Willis, M.A. 



Report of a Joint Committee of Physics and Meteorology referred to, 

 by the Council of the Royal Society, for an opinion on the propriety 

 of recommending the establishment of fixed magnetic observatories, 

 and the equipment of a naval expedition for magnetic observations 

 in the Antarctic Seas, to Her Majesty's Government, and to report 

 generally on the subject : together with the Resolutions adopted on 

 that Report, by the Council of the Royal Society. 



Report. — The subject of terrestrial magnetism has recently received 

 some very important accessions which have materially affected not 

 only the point of view in which henceforward it will be theoretically 

 contemplated, but also the modes of observation which will require to 

 be adopted for completing our knowledge of the actual state of the 

 magnetic phsenomena, and furnishing accurate data for the construc- 

 tion and verification of theoretical systems. It was for a long time 

 supposed that the changes in the position assumed by the needle at 

 any particular point on the earth's surface might be conceived as 

 resulting from regular laws of periodicity, having for their arguments, 

 1st, a great magnetic cycle of several centuries, depending on un- 

 known, and perhaps internal movements or relations ; and 2ndly, on 

 the periodic alternations of heat and cold depending on the annual 

 and diurnal movements of the sun. The discovery of the affection 

 of the needle by the aurora borealis, and of the existence of minute 

 and irregular movements, which might be referred either to unper- 

 ceived auroras or to other local and temporary causes, sufficed to 

 show that the laws of terrestrial magnetism are not so simple as to 

 admit of this summary form of expression ; and the important dis- 

 covery, first announced, we believe, by Baron Von Humboldt, that 

 those temporary changes take place simultaneously at great distances 

 in point of locality, a discovery which has since been remarkably 

 confirmed and extended to very great intervals of distance, so as to 

 include the whole extent of the European continent, by Gauss and 

 Weber, and their coadjutors of the German Magnetic Association, 

 has sufficed to show that the gist of the inquiry lies deeper, and 

 depends upon relations far more complex, while at the same time 

 the dominion of what might previously have been regarded as local 

 agency, would require, in the new views consequent on the esta- 

 blishment of these facts, to be extended far beyond what ordinary 

 usage would authorize as a just ai)plication of that epithet. 



