S76 Royal Society. 



procal action of magnets and metals during* rotation. He at the 

 same time establishes an important distinction among bodies which 

 had long been considered as associated by phenomena common to 

 them all • and gives indisputable evidence of electric action due to 

 terrestrial magnetism alone. An important addition is thus made to 

 the facts which have long been accumulating for the solution of that 

 most interesting problem, the magnetism of the earth. 



The Council have awarded another Copley Medal to M. Poisson, 

 for his work entitled Nouvelle Theorie de V Action Capillaire. In this 

 work a great variety of problems are solved relative to molecular 

 attraction, some of which had not before been attempted ; but the most 

 remarkable feature of the work is, the conclusion which the author 

 draws, namely, that the elevation and depression of liquids in capil- 

 lary tubes are essentially dependent on the rapid variation of density 

 which takes place at the surface of the fluid, and without which, 

 according to the author, that surface would continue plane; this is at 

 variance with the theory given in the Mecanique Celeste, although 

 indeed Laplace notices this change of density at the surface, as a 

 necessary consequence of the action of the molecules upon each other 

 (Supp., x. livre, p. 74.) The theorems and expressions of M. Poisson 

 do not differ in form from those of the Mecanique Celeste ; but the con- 

 stants which are involved in these equations are not expressed by the 

 same definite integrals. No difference ensues in the consequences 

 which are deducible from them, because the law of molecular attrac- 

 tion being unknown, it is impossible to arrive at the value of these 

 constants a priori, or otherwise than by observation. 



M. Poisson has calculated the vertical and horizontal pressures 

 upon a solid body plunged in a fluid : the value of the latter does not 

 agree with that given in the Mecanique Celeste. According to the ex- 

 pression of Laplace the body might take a motion of translation : to 

 this objections were formerly made by Dr. Young, and it will be noticed 

 with interest that these objections are now confirmed by M. Poisson. 

 The Council have awarded the Medal to the author, in order to testify 

 the high sense which they entertain of the importance of the researches 

 contained in the work in question. 



After the reading of the Report the Society proceeded to the elec- 

 tion of the Council and Officers for the ensuing year, when the 

 following was declared to be the list: — 



President: His Royal Highness the Duke of Sussex, KG. — 

 Treasurer: John William Lubbock, Esq. M.A. — Secretaries: Peter 

 Mark Roget, M.D., John George Children, Esq. — Foreign Secretary: 

 Charles Konig, Esq. 



Other Members of the Council : Francis Baily, Esq. ; Captain 

 Francis Beaufort, R.N. ; Mark Isambard Brunei, Esq.; Rev. Wil- 

 liam Buckland, D.D. ; Samuel Hunter Christie, Esq. M.A. 3 William 

 Clift, Esq. • Rev. James Cumming, M.A. • Benjamin Gompertz, 

 Esq. ; Joseph Henry Green, Esq. ; George Bellas Greenough, Esq.; 

 William George Maton, M.D. ; Roderick Impey Murchison, Esq.; 

 William Hasledine Pepys, Esq.; Stephen Peter Rigaud, Esq. M.A. ; 

 Rev. Richard Sheepshanks, M.A. ; Rev. William Whewell, M.A. 



