on the Baltic Sea. 379 
above all, at the time when the firft fnow appears, and in 
the beginning of the {pring. 
In the next place, the water of the Baltic is lefs faline 
than that of other feas; the caufe of which, in all proba- 
bility, is to be afcribed to the great number of rivers that 
fall into it. For this reafon its gravity is likewife lefs, and) 
yeffels cannot fail in it with the fame velocity as in the 
North Sea. For the fame reafon alfo it is more liable to 
corruption. The number of the ftreams which empty 
themfelves into this fea amount, according to Buffon, to 
forty; and among thefe the Oder, the Weichfel, &c. are 
the moft confiderable. Notwithftanding the great quantity 
of water fupplied by thefe rivers, the Baltic does not fenfibly 
increafe. Its principal efflux, towards the North Sea, is the 
Sound; though Englifh navigators have found there, at the 
depth of four or five fathoms, a funken current, running in 
a contrary direCtion to that at the furface. 
' The Baltic is not fubject to a regular ebbing and flowing, 
as it is furrounded by land, and is united, with the North 
Sea only by the Sound and the two Belts: this cireumftance 
has given occafion to its being called the inactive fea (mere 
pigrum). During a long continuance of the weft wind its 
natural efflux is prevented, and a great deal of water forced 
into it from the North Sea; fo that it then rifes on the 
eoalts a little above its ufual level. This conne@ion, how- 
ever; with the German ocean is fometimes the caufe that 
the ebbing and flowing of thie latter, though weak, co-_ 
déperates with the Baltic, fo that traces of their effects may 
be fometimes perceived. 
We are affured by hiftory that this fea has been fome-. 
times totally frozen during fevere cold. This was the cafe 
in the year 1333, at which time people could travel on the 
ice from Lubec to Pruffia and Denmark; and on this ac- 
count huts were ereéted in different places for the accommo- 
dation of travellers. A like phenomenon occurred in 1399 
and 1533; and in 1423 people could walk and ride over the 
4 fea 
