Hydrographical Observations from the Danmark Expedition. 287 



The nature of the bottom on the bank was mud or very soft 

 clay, and in the deeper channel near to land mainly sand and gravel. 



On the inner side of the deeper channel lie the fringe of islands 

 and the fjord systems, partly shut off by barriers at the entrances, 

 partly in communication with the submarine fjords, which transect 

 the Bank. 



The hydrographical investigations to be discussed later have shown 

 the close connection which exists between this topographical nature 

 of the bottom and the circulation of the water, a relation, however, 

 which is found everywhere. 



2. Fjords and sounds. 



a. Method of the observations. 



These soundings were made from the sledge in the autumn of 

 1907 and spring of 1908. 



A 5 kg. lead was used. The method of taking the soundings is 

 described in more detail later under the hydrographical observations. 



The soundings in Øresund, Lille Belt and a part of Stormbugt 

 (the waters in the neighbourhood of Danmarks Havn) were made in 

 the autumn of 1907 on the newly frozen autumn-ice. 



The soundings were taken along certain lines with a distance of 

 ca. 450 steps between each sounding. 



At every 3rd sounding the position was determined by measure- 

 ment of the angles towards the cairns in the triangle determined 

 astronomically. 



The time for each sounding was noted, so as to correct the 

 depths to the mean level of the water. 



The depths proved to be inexact, however, within an error of 

 Im., as the meter-wheel sometimes became frozen. The depth was 

 then measured by counting the number of turns of the drum ; but 

 as the line could not always be wound quite uniformly on this, ex- 

 periments were made, which showed, that the amount of accuracy 

 could not be taken as greater than that indicated above. 



The soundings in the Store Belt were made in the spring of 

 1908. As the ice at this time had a thickness of over Im., the tak- 

 ing of each sounding meant a fairly considerable amount of work, 

 and the number of soundings made was therefore not great. 



Time only permitted us to make a single line of soundings from 

 Koldewey Island across towards Teufelkap. 



In the spring of 1908 we also made some soundings in Mørkefjord 

 and some few soundings in Sælsø and Annekssø, as also in Dove Bugt. 



The nature of the bottom was determined in the ordinary way 

 by fixing tallow on the end of the lead. The samples were given to 

 the geologist for further investigation. 



