400 ON THE LEVEL 



tion, the following may be mentioned as tending to sup- 

 port the opinion of a fall of level. 



1st, It is generally believed among the pilots of 

 the Baltic, that the sea has become shallower along 

 the course which vessels ordinarily follow ; but, it is 

 added, that this alteration is more sensible in the places 

 where the tide collects sand, detached pebbles, and 

 sea-weeds, or in those where the bottom is composed of 

 rocks. The same observation has been made in the 

 neighbourhood of some large towns and fisheries ; for 

 example, a hydrographic chart made in 1771, gives six 

 fathoms for the mean depth of the sea opposite the har- 

 bour of Landskrona, whereas, in 1817, the sounding 

 line scarcely gave five fathoms at the same point. 



2d, According to the oldest and most experienced 

 pilots, the straits which separate the numerous islets 

 scattered along the coast of Sweden, from Haarparanda 

 to the frontiers of Norway, received vessels that drew 

 ten feet of water ; now they are not practicable for 

 boats that draw more than two or three feet. 



3d, The pilots further affirm, that, along the whole 

 coast of Bahusia, the bottom undergoes a diminution, 

 which becomes sensible every ten years in certain places, 

 where it is composed of rocks. Several other parts of 

 the Baltic may be cited, in which a similar change has 

 been remarked. 



M. C. P. Hallstrom, in an Appendix to Mr Bruncro- 

 na^s Memoir, gives the following table of the diminution 

 observed in the depth of the waters of the Gulf of 

 Bothnia. 



