390 



the validity of these new observations, unless the Professor was pre- 

 pared to show that his former ones were less worthy of confidence. 

 In reply to this, Professor Parrot, in his Appendix, admits that the 

 barometrical instruments used in 1811 were imperfect, and that his 

 former calculations also were in some respects inaccurate. 



It appears tome perfectly natural that Baron Humboldt, M. Arago, 

 and others, should have willingly admitted the supposed fact of a con- 

 siderable variation between the levels of the Caspian and Black Seas. 

 It is well known that the Mediterranean sustains its level at nearly 

 the same height as the ocean by drawing largely from the Atlantic 

 on one side and from the Black Sea on the other. But if these 

 constant supplies of water were cut off, if the Straits of Gibraltar 

 and Constantinople were closed, and the Mediterranean became an 

 inland lake isolated like the Caspian, its level must immediately fall. 

 Its loss, by evaporation, would not be counterbalanced by the influx 

 of river water, and there would then exist around its borders a tract 

 of dry land lower than the ocean. It is true that we have no data 

 for deciding to what extent this depression of level would reach ; but 

 it would present, at least on a small scale, a phasnomenon analogous 

 to that supposed to have been established in the case of the Cas- 

 pian. 



With every inclination to acknowledge and duly to appreciate the 

 honest zeal with which Professor Parrot has laboured to correct his 

 first error, I may remark that it does not yet appear why three or 

 four years were lost after 1829 in putting the scientific world on 

 their guard, and above all why the author of the Asiatic Fragments, 

 published in 1831, was allowed to remain in ignorance of results 

 previously obtained. 



Gentlemen, I have now endeavoured to lay before you a brief 

 sketch of the principal subjects referred to in the papers and in the 

 discussions which have engaged the attention of the Society during 

 the last year. I have confined myself exclusively to our own Pro- 

 ceedings ; for the limits of this address would not allow me to give an 

 analysis even of all the English works on Geology which have ap- 

 peared since our last Anniversary, still less of all those which have 

 been published on the Continent. A brief notice of these last would 

 indeed require a volume, and this fact alone should inspire us with a 

 feeling of strength and confidence in the futm'e progress of Geology, 

 which although it had scarcely obtained a recognized place amon^ 

 the sciences towards the close of the last century, has already risen 

 into such importance as to excite a general interest in every nation 

 throughout the world where the works of nature are studied. 



