130 



any motion in the interior fluid, in wliich the rotatory motion causing 

 precession and nutation is produced indirectly by the effect of the 

 same forces on the position of the solid shell. A modification is thus 

 produced in the effects of the centrifugal force, which exactly com- 

 pensates for the want of any direct effect from the action of the dis- 

 turbing forces; a compensation which the author considers as scarcely 

 less curious than many others already recognized in the solar system, 

 and by which, amidst many conflicting causes, its harmony and per- 

 manence are so beautifully and wonderfully preserved. 



The solution of the problem obtained by the author destroys the 

 force of an argument, which might have been urged against the hy- 

 pothesis of central fluidity, founded on the presumed improbability 

 of our being able to account for the phenomena of precession and 

 nutation on this hypothesis, as satisfactorily as on that of internal 

 solidity. The object, however, of physical researches of this kind 

 is not merely to determine the actual state of the globe, but also to 

 trace its past history through that succession of ages, in which the 

 matter composing it has probably passed gradually through all the 

 stages between a simple elementary state and that in which it has 

 become adapted to the habitation of man. In this point of view the 

 author conceives the problem he proposes is not without value, as 

 demonstrating an important fact in the history of the earth, pre- 

 suming its solidification to have begun at the surface ; namely, the 

 permanence of the inclination of its axis of rotation, from the epoch 

 of the first formation of an exterior crust. This permanence has 

 frequently been insisted on, and is highly important as connected 

 with the speculations of the author on the causes of that change of 

 temperature which has probably taken place in the higher latitudes : 

 all previous proofs of this fact having rested on the assumption of 

 the earth's entire solidity ; an assumption which, whatever may be 

 the actual state of our planet, can never be admitted as applicable 

 to it at all past epochs of time, at which it may have been the habi- 

 tation of animate beings. 



The author concludes, by expressing a hope that he may be enabled 

 to prosecute the inquiry still further, and to bring before the Royal 

 Society, at a future time, the matured results of his speculations. 



March 14, 1839. 



JOHN W. LUBBOCK, Esq., Vice-President and Treas., 

 in the Chair. 



G. W. Featherstonhaugh, Esq., who at the last Anniversary had 

 ceased to be a Fellow from the non-payment of his annual contribu- 

 tion, was, at this Meeting, re-admitted by ballot into the Society, 

 agreeably to the provision of the Statutes. 



Clement Tudway Swanston, Esq., was balloted for, and duly 

 elected into the Society. 



A paper was read, entitled, " An Experimental Inquiry into the 



