1825.] New Scientific Books. 77 



That the numbers in the last column, however^ represent the 

 exact amount of the secular depression, cannot be regarded as 

 fully determined, because it has not yet been satisfactorily ascer- 

 tained whether the diminution be uniform, or whether it varies 

 at difrerent periods; and whether it is in any respect dependent 

 on local circumstances, or on the cUmate, or on the state of the 

 atmosphere. Neither has it been ascertained whether this 

 depression, which has been remarked to become less and less 

 from the north of the Baltic towards the south until it finally 

 becomes insensible, diminishes in an equal proportion with the 

 latitude, or Avhether it follows a different law. Throughout the 

 whole of the Gulf of Bothnia, the i'all appears to be uniform, and 

 its amount for the la^it 100 years appears to be about 4^ feet; 

 below, at Calmar, it is only 2 feet ; but whether the diminution 

 between these two stations takes place in a regular progression 

 is still undecided. 



Before concluding, we have only to remark, that this sup- 

 posed fall of the level of the Baltic must not be regarded as dis- 

 proved by the issue of the long agitated inquiry, whether the 

 level of that sea is actually higher than that of the German 

 Ocean, and which the observations made of late years at the 

 locks of the canal of Holstein appear to have answered decidedly 

 in the negative. Neither can an absolute fall be accounted for 

 by M. Olto's theory, that the sea in one position is gaining in 

 depth exactly what it loses in another; a shifting \vhich he 

 attributes to the banks becoming in some situations more 

 extended, and the bottom more elevated, in consequence of the 

 immense quantities of earth, sand, stones, &.c. whndi are annually 

 carried down by the large rivers which disembogue themselves 

 into the Baltic."^ Admitting the accuracy of the observations as 

 they are recorded on the rocks themselves, we must also admit 

 either that the rock constituting the bottom of that sea is actually 

 elevated by some subterraneous process, or that irs waters are 

 either diminishing by evaporation, or are retiring to some other 

 quarter of the globe. The latter explanation is supported by 

 numerous authentic analogical changes, with which every one 

 at all conversant in the history of the earth is familiarly ac- 

 quainted ; while there are no geological facts at present known 

 which bestow any degree of plausibility upon tlie former. 



AUTICLE XIV. 



NEW SCIENTIFIC BOOKS. 



PREPARING FOR PUBLICATION. 



Mr. Bewick is preparing a work on British Fishes, in the style of 

 Iiis prccedii);,' vohuiit's on (-iuMdrupfils and Birds. 



