75 



pegede, og det er derfor helt naturligt, naar Undersøgel- 

 serne ikke i Henseende til Studiet ;ii' tidligere ukjendte 

 Eiendommeligheder ved Havet kunde føre til saa fyldige 

 Resultater, som ønskeligt kunde være. Men om end disse 

 Dndersøgelser paa Grund heraf nærmest faa Karakteren af 

 forberedende Arbeider, saa vil del dog, som jeg haaber, 

 indrønvmes, at de desuagtet kunne have sine maaske ikke 

 uvigtige Følger, idet de vise. al man gjennom de chemiske 

 Observationer. der tidligere i Sammenligning med Tempe- . 

 råtur- og Dybdebestemmelser har spillet en mindre frem- 

 tredende Rolle ved Studiet af Havets Physik, vil kunne 

 skafte Oprysnjnger om mærkelige Forholde i Havet, som 

 man ad anden Yei vanskelig skulde takle paa at søge op- 

 klarede. Man vil ved Hjælp af de her erholdte Resultater 

 med Lethed i Fremtiden kunne udkaste en detailleret' Plan 

 for en fornyet Undersøgelse af det norske Hav, der i mine 

 Øine stiller sig som særdeles ønskelig, da man ved at gjøre 

 et hidindtil ukjendt Har til Gjenstand for Bearbeidelse 

 vanskelig turde gjøre Regning paa at træffe et, der i Hen- 

 seende til Studiet af Strømforholdene er saa instructivt 

 som det norske Hav. 



Ved saadanne fremtidige Undersogelser kunne de paa 

 den norske Expedition benyttede Arbeidsmethoder ikke i 

 alle Retninger blive optagne i uforandret Form, og det vil 

 derfor ikke være ubefoiet til Slutning med faa Ord at paa- 

 pege de Mangler, der klæbe ved disse. 



De til Saltbestemmelserne tidligere benyttede Metho- 

 der, ifølge hvilke alle herhen horende Observationer an- 

 stilles ombord, bør utvivlsomt tor Fremtiden ikke komme 

 til Anvendelse, da man ad den Yei tiltrods for al anvendt 

 Møie ikke vil kunne opnaa den Nøiagtighed, som tiltrænges 

 for med onskelig Sikkerhed at kunne paavise de i Havet 

 forekommende ofte meget smaa Differentser. Paa den 

 norske Expedition blev denne Fremgangsmaade benyttet, 

 fordi man med ældre Iagttageres Udtalelser for Øie maatte 

 befrygte, at Sovand ikke lod sig opbevare i længere Tids- 

 rum uden at uudergaa forskjellige Forandringer, en Frygt, 

 der imidlertid efter min Erfaring kun forsaavidt er be- 

 grundet. som man til Opbevaring af Våndet benytter Kar, 

 der ere forsynede med Korkeprop. Jeg bar nemlig under- . 

 søgt flere Vandprøver, der have været opbevarede paa 

 denne Maade i omkring 2 Aar og fundet, at de alle uden 

 Dndtagelse have undergaaet Forandringer af saadan Art, 

 at man turde være berettiget til at anse dem uskikkede 

 til Egenvægtsbestemmelse, bvorimod jeg bos Vandprøver, 

 der i lignende Tidsrum kavde henstaaet paa Flasker for- 

 synede med isleben Glasprop, ikke kunde opdage nogen- 

 somhelst Eiendommeligheder, der kunde adskille dem fra 

 friskt øste Vandprover. Ved denne Opbevaringsmaade 

 risikerer man dog ganske sikkert Fordunstning af en Del 

 af Våndet, og man lnaa derfor beskytte sig mod denne 

 Feilkilde ved at hjemføre det til Saltbesteinmelser be- 

 stemte Vand paa tilsmeltede Glasrør. 



I de saaledes conserverede Vandprøver vil man senere- 

 hen efter Hjemkomsten kunne bestemme Egenvægten ved 

 Sprengels P)'knometer og Cklorgekalten • ved Hjælp af Vei- 

 ningsanalyser med saadan Skarpbed, som man ved Arbeide 



servations, and hence the results of the work done. em- 

 bracing as it did the investigation of phenomena unknown 

 before, were naturally less comprehensive than migbt other- 

 wise have been attained. But. though such labours must 

 to a certain extent, be regarded as prelfminary, they will, 

 I trust, prove of considerable importance, showing as they 

 do. that chemical observations. which, as compared with 

 determinations of tempe.rature and dejitli. previously held 

 quite a subordinate rank among the means employed for 

 studying the physical conditions of the ocean, will serve to 

 throw light upon many remarkable phenomena. that without 

 suck data would be extremely ditticult to explain. < hi 

 the basis of the results kere set fortk. a detailed plan 

 might be easily laid down for the furtker exploration of 

 the Norwegian Sea, — in my opinion a most desirable un- 

 dertaking, since of ocean tracts as yet unknown, there are 

 probably few that. in regard to the study of ocean cur- 

 rents. would so well repay investigation as that section of 

 the North- Atlantic. 



As several of the methods of investigation practised 

 on the Norwegian Expedition, will not admit of being 

 adopted on tuture occasions in a wkolly unmodified form. 

 it will not be out of place in conclusion briefly to point 

 oiit tbeir tlefects. 



Tke methods previously devised for determining the 

 amount of salt in sea-water, by which all observations with 

 this object in view were tåken on board, should unquestion- 

 ably cease to be adopted, since they will not suftice. witk 

 the greasest care even, to attain tke kigb degree of accu- 

 racy requisite for detecting suck minute differences as are 

 frequently found to oCcur. Tkese defective modes of op- 

 eration were. however, adopted on the Norwegian Expedi- 

 tion, tkere being reason to believe from the statements of 

 earlier observers, that sea-water could not be piæserved 

 for any length of time without u-ndergoing chemical change, 

 a supposition which, so far as my experience goes, is con- 

 firmed only in tke event of its being kept in corked vessels. 

 I kave examined, for instance, various samples of sea-water 

 that bad been preserved for about 2 years in corked bottles, 

 and found all without exception to kave undergone a change 

 sufticient to render tkem unfit for specific gravity determ- 

 inations; wkereas. on tke otker kand, sea-water which had 

 been allowed to stand over for the same space of . time in 

 bottles furnished with ground glass stoppers, was not to be 

 distinguished from freshly drawn samples. Theré is, how- 

 ever. a risk of loss from evaporation. the stoppers being 

 seldom, if ever, tight-titting ; and to guard against this 

 source of error, the water for salt-determinations must he 

 brougkt korne in kermetically sealed glass tubes. 



Witk water tbus preserved, tke specitic gravity may 

 be determined by means of Sprengefs pycnometer, and the 

 'amount of chlorine by weighing, on the return of the Ex- 

 pedition. far more accurately than would be possible on 



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