The North Sea and Skagerak 
mean high-water above mean low-water 
Waters inside Skagen 
the mean height of the spring-tide 
Thyborøn channel .. 1 foot 6 inches Slipshayn....... 1 foot 
ASSEr in. kk URL 1 — 1 — Helsinger....... , — »o inches 
Sleep cuccueceoc l'US Copenhagen OT 
Skagen. IHRER 1 — , — 
The figures for the places inside Skagen are so small that they are often 
neutralized by the change of level caused by the winds. The wind’s influence on 
the height of the water-level is at many places very distinct and well known. 
Thus, westerly winds cause a high level of the water in the Kattegat on account 
of the influx of water from the Skagerak, while easterly winds cause a low level 
of the water. With the variable winds, so pronounced in our country, the changes 
in the level of the sea are also very variable; but as certain directions of the 
wind are predominant at certain seasons, others at other seasons, the average height 
of the water-level is also different at different periods of the year. From Apam 
PAULSEN a general summary is given here of the average deviations of the water- 
level at three different places on the Danish coasts from the height of the mean 
-water-level during the twelve months of the year, calculated as the averages of 
observations made during the years 1889—1902!. 
The annual variation of the height of the water-level. 
Station | Jan. | Febr. March April | May | June | July | Aug. | Sept. | Oct. | Nov. | Dec. 
| em | cm em | em | cm | em | cm em | em | em | em | cm 
Hirshals.......... |—0,3'|—4,6 | 88 | 10,8] 10722 | 512 | 72 | ss | 66 | 37 664) 
Frederikshayn .... 1,2 4,7 —7,4 11,6 9,6 | —3,2 | 3,9 | 5,5 6,6 6,7 | 5,3 | 7,3(5) 
Eredericia tete 0,6 2,1 4,5 | — 6,6| — 54 —2,6 | 13 | 28 | 51 | 60 | 34 | 2,6(2) 
The numbers in parenthesis for December indicate the annual mean-height of 
the water during this month, when the extraordinary. mean-height for December 
1898 is left out of consideration. 
It appears from this, that the lowest water-level at all three places is in April, 
and it is in agreement with this, that easterly winds according to simultaneous 
observations are most predominant in April. This condition is of the greatest im- 
portance to the upper littoral vegetation, and it is the reason why an upper belt 
of vegetation, which has grown perfectly well during the course of the winter, is 
killed every spring. 
Division of the Danish waters. To facilitate the summary over the di- 
stribution of the Algæ, I have not only maintained the ordinary divisions, but have 
also made further subdivisions in the Kattegat and Baltic. These will be found 
! ADAM PAULSEN, Meddelelser om det danske meteorologiske Instituts Vandstandsmaalinger. (Ac- 
count of the measurements of the height of the sea-level, carried out by the Danish Meteorolog. Insti- 
tute). Nautisk-Meteorologisk Aarbog 1906, København 1907, 
