SiiCT.IV.] (Ecology, 2.S1 



same name, but a much more sober and rational 

 inquirer. In 1799 M. L. Bertrand of Geneva, 

 published a work* which was intended to aceoinit 

 for the })henomena of the p^lobe we iuiiabit. This 

 gentleman supposes, witli Dr. Halley, that there is 

 a magnetic nucleus enclosed and suspended in a 

 hollow space in the centre of the earth. This 

 has a rotatory motion of its own, and an inclina- 

 tion of its magnetic axis to the axis of rotation, 

 thus causing an oscillatory motion in the magnetic 

 poles. While things were in this situation, he 

 supposes that a Comet of ordinary size and charac- 

 ter approached our earth, displaced the nucleus 

 from the centre, removed it toward one side, and 

 changed the centre of gravity of the earth. These 

 circumstances occasioned the derangement of the 

 seas, their removal to other parts of the globe, the 

 immersion of old and the emersion of new conti- 

 nents. This theorist is a disciple of M. de Saus- 

 suref ; and the principal design of his work seems 

 to have been to show the possibility of that sudden 

 retreat of the ocean which his n^aster believed and 

 taught, £ind to account for that event and the sub- 

 sequent elevatipn of the land wliicli before formed 

 jt-s bottom. — — c 



The last person to be mentioned, as having ad- ^ 

 ventured in this ample field of speculation anc^ 



* Renouvdlancns Fcriodlqucs, kc.j par L. BertraiKl, &:c., Svo, 



1/99. 



t jM. dc Saussure had promised to give a geological sy.^teni at 

 the end of his Travels over the Alps; but, after nuny years, he 

 contented himself witli inforiyiing the public, tlnU the result o\ 

 his investigations induced him to believe, that the whole of our 

 ^•ontihents had been formed under the sea, bad been arranged by 

 jts action, and were left dry by a pr.H'ipitate retreat of its waters. 



