Hydrographical Observations from the Danmark Expedition. 379 



The observations were made from the ship partly from the aft 

 end, partly from a hole in the ice (a fire-opening) at the forepart of 

 the ship, and the depth of these places varied between 5 and 16 m. 



Throughout the whole winter the salinity was nearly the same 

 from surface to bottom and the temperature was the freezing point 

 temperature corresponding to the salinity (see series XLVII- — L and 

 LIII). The sahnity rose in the course of the winter, partly owing 

 to separation of the chlorides when the sea-water froze, partly 

 owing to intrusions from the deeper layers on the barrier further 

 out in Øresund. 



At the end of July the rivers began to flow and as the ship lay 

 off such a river, the warm water from the melting snow and ice (with 



a temperature of -f 10 hl5°C.) streamed down over the ice and 



attacked this both from above and from the side. The consequence 

 was, that the ice round about the ship melted away in the course of 

 about ten days, though it still remained a long time in the outer 

 part of the harbour and in Øresund. 



In 1907 the rivers began to run on June 28th, on July 6th the 

 ship was free of ice, but it was not until August 13th, that the ice 

 broke up in the outer part of the harbour and in the fjord. In 1908 

 the dates were June 18th, July 4th and 18th. 



From this period we have the series XXXVII, XXXVIII, XL, 

 LXX and LXX and LXXI, which show, how the downflow of warm 

 river-water spread out over the very cold and sahne surface-water 

 in the harbour as a layer whose thickness was nearly the same as the 

 average thickness of the ice in the outer part of the harbour. For 

 example, on July 18th 1907 the average thickness of the ice was ca. 

 1.8 m. and the depth of the warm, almost fresh layer was likewise 

 ca. 1.8 m. (series XXXVII): on July 27th the thickness of the ice 

 had decreased to a little over 1 m. and that of the warm layer was 

 also between 1 and 1.5 m. (series XXXVIII). 



During this time there was a sharp boundary between the fresh 

 and the salt water. 



As soon as the ice broke up in the outer part of the harbour and 

 the fjord, the warm and fresh water became mixed with the cold and 

 salt water to form a nearly homogenous mass (series XLI and LXXI). 



In September cooling of the uppermost layer began, as also for- 

 mation of ice and then followed again an increase in salinity. 



The series from the fjords and sounds at ca. 76° N. L. in North-East 

 Greenland. (Series LVI, LVIII, LIX, LXI). 



Three entrances led into Stormbugt and Dovebugt: Øresund, 

 Store Belt and Lille Belt. Of these the Store Belt was in free commun- 

 ication with the Greenland Sea down to a depth of over 300 m., whilst 



