semes Vedkommende af saadan Størrelse, at de i Sammen- 
ligning med de sraaa Differentser, som det her gjældev at 
paavise, lettelig paa sine Steder kunne gjøre sig gjældende 
og frembringe Uoverensstemmelser, hvor de i I ilfælde at 
absolut nøiagtige Observationer ikke vilde tindes. 
Hvilke'n Vægt man nu end vil tillægge disse faaFor- 
skjelligheder mellem de to Karter, saa meget er dog sikkert, 
at de kun optræde som Undtagelser, medens den langt stæi- 
kere fremtrædende Regel er Overensstemmelser ai saadan 
Art, at de ikke uden videre kunne tilskrives Tilfældiglieder. 
Der existerer uimodsigeligt en paa mange Puncter næsten 
til Proportionalitet grændsende lovmæssig Forbindelse mel- 
lem Saltgehalten og lvvælstofmængderne. som muligens ikke 
turde lade sig forklare paa anden Maade end netop gjen- 
nem den for omtalte Hypothese. som saaledes maa ansees 
for at indebolde ialfald en stor Del Sandhed, idet den 
samtidig bestyrkes af to af hinanden fuldstændig uafhængige, 
uensartede Observationsrækker, der i alt Væsentligt give 
det samme Resultat. 
Den, som det synes, største Vanskelighed ved denne 
Hypothese bestaar i at forklare, hvorledes det i de store 
Dyb flydende atlantiske Vand skulde have antaget en saa 
lav Temperatur, som det ifølge Observationerne viser sig 
at besidde. Dette turde dog inaaske ikke synes saa urime- 
ligt, uaar man betænker, at den varme, søndentra kommende 
Atlanterhavsstrøm ved at flyde henover det underliggende 
meget kolde Vand paa de nærmest til dette grændsende 
Lag maa blive udsat for en meget stærk Al kjøling neden- - 
fra, og at det først gjennem • en saadan Afkjøling til om- 
kring 0° opnaar den hoie specifiske Vægt, der er den nød- 
vendige Betingelse for. at det skal kunne synke tilbunds. 
Det atlantiske Vand har altsaa, allerede førend det begyn- 
der at synke, antaget en meget lav Temperatur og vil 
desforudén- under selve Synkningen, idet det da kanske i 
et meget langt Tidsrum belinder sig paa alle Sider omgivet 
af polart Vand, end yderligere blive Gjenstand for Afkjø- 
ling, førend det naar Bunden. Det fremgaar forøvrigt 
ogsga af de endnu ikke offentliggjorte Temperaturobserva- 
tioner. som jeg desuagtet ved Velvillie af Professor Molin 
har faaet Anledning, til at gjøre mig bekjendt med, at 
Temperaturen i de store Dyb paa de med rød Farve be- 
tegnede Partier er no'get høiere end der, hvor Kartet er 
farvet blaat, saaledes at i Virkeligheden ogsaa Temperatur- 
forholdene tale for den opstillcde Hypothese. 
Det vilde dog være paa urette Sted paa dette Sta- 
dium at. forsøge * udredet alle Vanskeligheder, saalænge de 
paa Expeditionen udførte talrige Temperaturbestemmelser 
endnu ikke ere forelagte Offentligheden, da man alene ved 
at tage tilbørligt Hensyn til det hele foreliggende Materiale 
af Observationer vil kunne vente at faa det bedst mulige 
Indblik i de mere indviklede Spørgsmaal om Strømforhol- 
dene. Det er dog meget sandsynligt, at man senereheu 
ved at combinere alle Data vil kunne kaste Lys over me- 
get, som nu maa synes dunkelt. 
Uheldigvis var det ved Expeditionens Udreise* ikke 
muligt at forudse. at de chemiske Observationer skulde 
kunne føre. til Slutninger af saadan Art som de lier paa- 
of the computations, they might easily affect the result, 
and give rise to discrepancies which, with perfectly accurate 
observations, there would be no fear of. 
Whatever weight may be attached to these differences, 
they must unquestionably be regarded as exceptional; the 
rule is agreement, and of a character precluding the possi- 
bility of ascribing it to chance. Many ot the observations 
prove incontestibly the existence of a definite, well nigh 
proportional connexion between the amount ot salt and 
that of nitrogen, “a connexion difficult, perhaps, to explain 
without having recourse to the aforesaid hypothesis, which 
cannot but come near the truth, confirmed as it is by 
two widely different series of observations, leading, each 
independently of the other, in all essential points, to the 
same result. 
The greatest apparent difficulty involved in this hypo- 
thesis consists in explaining the low temperature of the 
Atlantic water in the deeper strata. We must, however, 
bear in mind that the warm Atlantic current, in flowing 
over the cold ‘water of the lower strata, is necessarily 
made to part with a very considerable amount of heat; 
and that the high specific gravity, without which it could 
not sink to the bottom, involves a temperature of about 
0°. Hence, the Atlantic water will have acquired a very 
low temperature before beginning to sink, and moreover, 
being surrounded during its downward passage, possibly 
for a considerable period, by Polar water, give off a further 
amount of heat ere it reaches the bottom. For the rest, 
it appears from the independent series of temperature 
observations, not yet in print, with which Professor Mohn 
has kindly made me acquainted, that the temperature at 
great depths in the sections coloured red in the Plate, 
is somewhat higher than in those coloured blue ; and hence 
the hypothesis adopted here derives additional support from 
the variation in temperature. 
Meanwhile, it would be premature to attempt dis- 
posing of all difficulties, till the numerous temperature 
determinations performed on the Expedition shall have 
been made public, since to elucidate fully the more intri- 
cate questions connected with ocean currents, the whole 
stock of materials must be dealt with. We may however 
venture to hope, that, at a later stage of this interesting 
inquiry, a general combination of data will throw light 
upon much that is at present involved in obscurity. 
Unfortunately, it was not possible to foresee on the 
departure of the Expedition, that such inferences as those 
here, pointed out would be drawn from the chemical ob 
