409 
Scientific InteUig ence. —Hydrog rarphy. 
followed different laws in different parts of the Baltic. In the 
Gulf of Bothnia, it has been estimated at four feet in the cen- 
tury. From this it diminishes southward, so as to be limited to 
two feet in the century, upon the coast of Calmar ; and there is 
reason to think that no diminution at all has taken place in the 
southern part of this sea ; and that, if any in its eastern part, it 
must at least be very small. — Admitting the reality of the phe- 
nomenon such as we have above announced it, and which ap- 
pears to be now admitted by the greater number of the Swedish 
naturalists, there remain many important questions to be an- 
swered. 1 st, What is the total quantity of the diminution pro- 
duced in the level of the Baltic, at a given point, and in a given 
period of time ? There still prevails much uncertainty on this 
subject ; and anomalies exist, which, in points very near upon 
each other, are in the relation of one to four, and even of one to 
twelve. Qdly, Has this lowering of the Baltic taken place in a 
uniform manner ? Are its variations, if any there be, regular or 
irregular, and subordinate to appreciable causes, such, for exam- 
ple, as is the case with the state of the atmosphere ? 3dly, Is the 
diminution observed on proceeding from north to south, and 
which becomes at length evanescent, proportionate to the lati- 
tudes, or subjected to other laws. Such must be the object of 
the further inquiries of observers ; for the establishment of the 
fact is of little importance, without a knowledge of the laws by 
which it has been regulated. But this is a difficult task to per- 
form. It is not, in fact, sufficient to form a correct estimate of 
the action of local changes which may have affected certain points, 
without influencing the general mass of water in the Baltic ; and, 
with this view, to choose, as places for marking, the most isolated 
rocks, the most remote from the shores, and situated in the deep- 
est water. It is further necessary to be assured, that the com- 
parative observations have been made when the sea was in a per- 
fectly similar state. In fact, the Baltic, without having any ebb- 
ing and flowing, is subject to a balancing of its waters, depen- 
dent upon the direction and power of the winds. It rises when 
strong north-west winds, of long continuance, have driven in the 
waters of the Northern Ocean, by the Cattegat, the Sound, and 
the Belt. It falls, on the other hand, after a continuance of 
winds blowing in a direction calculated to propel its waters to- 
