68 



afgrændser sig mod det indenfor Sydende meget ferskere 

 Vand. Forøvrigt. holder Grændsen for det saltere Over- 

 fladevand sig meget langt tilhavs med Undtagelse af, at 

 den ved den 70de Breddegrad paa en ganske kort Stræk- 

 ning kaster sig tæt ind under Kysten. 



Denne Fortynding af Overfladevandet, som overalt 

 ytrer sig ved den norske Kyst, er intetsteds ledsaget af 

 QOgen væsentlig Forrykkelse af Overfladetemperaturen. Salt- 

 gehaltens-Formindskelse skyldes her aabenbart det fra Rys- 

 terne udstrømmende Flodvand, der om Sommeren besidder 

 en ikke ringe Varmegrad, saaledes at man i den mest 

 fremtrædende Kyststrom langs Norges Vestkyst endog lin- 

 der en noget høiere Overfiadetenrperatur end paa nærlig- 

 gende Puncter. • Ganske anderledes stiller Sagen sig paa 

 den mod den østgrønlanske Polarstrøm vendende Side, 

 hvor Overfladevandet fortyndes ikke ved Flodvand men 

 ved det ved Havisens Smeltning dannede, stærkt afkjølede 

 Ferskvand, og det viser sig derfor, at en Synken i Saltge- 

 halten her bestandig er ledsaget af en tilsvarende Formind- 

 skelse af Overfladetemperaturen. Grændsen for det saltere 

 Vand i Overdåden følger derfor paa denne Side ofte Po- 

 larstrommens Grændse, og selv der, hvor den forlader 

 denne, optræder der dog ' samtidig med Overgangen fra 

 saltere til ferskere Vand altid meget tydelige Variationer 

 i Temperaturen, der gaa i samme Retning som Saltgehal- 

 tens. At Overfladetemperaturen synker, naar man enten 

 nærmer sig eller overskrider Grændsen for 3.50 °/„ Salt, 

 vise Observationerne No. 115 til 120'og No. 207 til 209. 



I selve Polarstrømmen er Saltgehalten i Overdåden i 

 nogen Afstand fra Grændsen oftest fundet meget lav, kun 

 paa et iSted optræder i saa Henseende en Undtagelse fra 

 den almindelige Regel, idet der omtrent paa den 75de 

 Breddegrad skyder sig en smal Tunge med Vand af høiere 

 Saltstyrke ind over Polarstømmen, uden at der dog derved 

 bevirkes nogen væsentlig Forhøielse af Overfladetempera- 

 turen. En Mærkelighed, som fortjener at omtales, er den, 

 at Professor Dr. G. 0. Sårs, som paa Expeditionens Tog- 

 ter jevnlig undersøgte Dyrelivet i Overdåden, netop paa 

 dette Punct langt inde i Polarstrømmen har gjenfundet de 

 for det varmere Atlanterhavsvand eiendommelige Dyrefor- 

 mer, der forresten intetsteds ellers ere fundne i den øst- 

 grønlandske . Koldvandsstroni. 



Med Hensyn paa Saltmængderne i de større Dyb 

 , henvises til Kartet No. II. hvori paa samme Maade som 

 ovenfor tindes indtegnel Saltgehalten ved HavbundeD samt 

 i de intermediære Dyb, forsaavidt Observationerne refererer 

 sig til Puncter saa dylit under Overdåden, at Temperatu- 

 ren der ligger under 0°. Hvor en Observation hidrører 

 i et intermediært Dyb, er Tallet i Kartet imderstrøget. 



Naar man bortser fra enkelte i Nærheden af Kys- 

 terne og paa grundt Vand optagne Vandprøver, varierer 

 Saltgehalten paa de store Dyb mellom 3.59 og :-5.45 "/„, 



of the salt ocean-water of the. Atlantic, distant but a few 

 miles from land. its boundary being distinctly marked by 

 the limits of the brackish water flowing along the shore. 

 Except in this region, and a locality bordering the 70th 

 parallel of latitude, where, for a short distance, it runs 

 close to the coast, the boundary of the salt surface-water 

 lies far out at sea. 



This- dilution of the surface-water on all parts of the 

 Norwegian coast is not any where found to exert a material 

 induence on the surface-temperature. The decrease in the 

 a mo unt of salt must he obviously ascribed to the influx of 

 river-water. the temperature of which during the summer 

 months is relatively high. — so high indeed, that the 

 principal coastal current, flowing along the western shores 

 of Norway, has a somewhat higher surface-temperature than. 

 that observed in its immediate vicinity. Phenomena the 

 reverse of these preva.il in the tract of ocean exposed to 

 the induence of the Arctic, or East Greenland, current. 

 There, the surface-water is not diluted by an influx of river- 

 water, but with freshwater of a, low temperature, produced 

 by the.melting of drift-ice; and hence a decrease in the 

 percentage of salt is invariably attended with a correspond- 

 ing reduction bf the surface-temperature. The salt surface- 

 water borders, therefore, not infrequently the Arctic current; 

 and even where its boundary diverges from it, the transi- 

 tion from salt to comparatively fresh water is always ac- 

 compained by a very considerable variation in temperature, 

 proportionate to the variation in the amount of salt. That 

 the surface-temperature becomes gradually lower on ap- 

 proaching the limits of the section in which the proportion 

 of salt is 3.50 per cent, will be seen from the series of 

 observations Nos. 115—120 and Nos. 207—209. 



In the Arctic current, some distance from its extreme 

 boundary, the proportion of salt at the surface was found 

 to be very small, except in one locality, near the 75th 

 parallel of latitude, where a narrow strip of salter water 

 dows into the current. without, however, causing an appreci- 

 able rise in the surface-temperature. It is a remarkable 

 fact. which must not be passed by unnoticed, that Profes- 

 sor G. 0. Sårs. naturalist to the Expedition. found here 

 in the surface-water, which he examined from day to day, 

 forms of animal life peculiar to the wa.ru area of the 

 Atlantic water, which he never met with in any'othér part 

 of the cold East Greenland current. 



As regards the amount of salt observed at great 

 doptlis. the reader is referred to Pl. II. in which. as in 

 Pl. I. will be found the percentage both at the bottom 

 and at intermediate depths, provided the observations were 

 tåken with samples of water the temperature of which in 

 situ was belowO". Observations with water from interme- 

 diate depths are denoted by underlining the figures ex- 

 pressing their res"ults. 



Disregarding a few samples of water collected near 

 the Coast and in shallow spots, the proportion of salt. 

 where the depth is great, ranges trom 3.59 to 3.45 per 



