19 



— 7.7H — 0.2 t -f- 0.01 lp / K 



som istedetfor de observerede Værdier 7.77 6.93 6'.29 

 giver 7.79 6.92 6.29 



Men Hensyn paa den relative Sammensætning af den 

 absorberede Luft da er den ikke saaledes som af Bunsen 

 for destilleret Vand fundet, uafhængig ai' Temperaturen 

 men varierer mrd denne, saaledes at Surstofprocenten paa 

 Strøget fra 0° til 15° forandrer sitr med en hel Proeent. 



Betragter man Resultaterne af disse Forsøg som Norm, 

 viser det sig, at den relativt til den samlede Luftmængde 

 meget hoie Surstofgehalt, som er observerét i < Iverfladen i 

 den nordlige Halvdel af det undersøgte Hav. i Virkelig- 

 heden skriver sig fra en ( (vermætning med Surstof og ikke. 

 som man ogsaa kunde tænkt, fra en mangelfuld Mætniug 

 med Kvælstof, idet der mærkeligt nok her tindes en Sur- 

 stofgehalt, der meget hyppigt overskrider den af disse For- 

 sov beregnede med 0.5 CC. og derover. Det vil sige. der 

 optræder saa store Aivigelser, at de paa ingen Maade kunne 

 tilskrives Observationsfeil, og det viser sig saaledes. at Sur- 

 stofgebalten i Overfladen ikke alene afhænger af Tryk og 

 Temperatur, men rimeligvis ogsaa maa paavirkes ■ af en 

 eller flere andre ubekjendte Aarsager. 



Naar det gjælder nærmere at studere Surstofmængdens 

 Variation med Dybden, falder det bekvemmest at udtrykke 

 den som Procenter af den samlede Luftmængde, da den 

 absolute Luftmængde varierer i meget stærkere Grad med 

 Temperaturen end Luttens relative Sammensætning, og man 

 vil saaledes ved at benytte denne Ddtryksmaade opnaa at 

 gjøre sig i betydeligt større Udstrækning uafhængig af 

 Temperaturens Indrlydelse. 



Ordner man de paa denne Maade udtrykte Tal etter 

 Dybden, viser det sig. at der med Hensyn paa Surstof- 

 procentens Størrelse i de forskjellige Dyh existerer en tem- 

 melig udpræget Lovmæssighed, som nærmere kan karak- 

 teriseres af nedenstaaende Tabel, der er uddraget af samt- 

 lige Observationer, naar undtages de to. hvor Udkogningen 

 ikke foretoges strax men forst efter nosen Tids Henstand. 



= 7.79 — 0.2 1 + 0.005 1 2 . 



giving 7.71) 6.92 6.29 



in place of the valnes observed . 7.77 6.93 6.29 



Hence. the relative Composition of the air alisorbed is 

 not. as Bunsen found to be the case with distilled water, 

 independent of teniperature, hut varies with that factor. 

 the percentage of oxygen. for instance. differing as much 

 as 1 per cent between 0° and 15". 



Now. assuming the results of these experiments to 

 furnish a normal standard, the relatively large proportion 

 of oxygen as compared with the total amount of air present 

 in 'the surface-water of the nortbern tracts of the sea in- 

 vestigated, will be found to arise from supersaturation with 

 oxygen. and not. as might be supposed. from imperfect 

 saturation with nitrogen, seeing that tbe proportion of 

 oxygen exceeded that computed from these experiments by 

 as much as. or even more tban, 0.5": for a difference so 

 considerable does not admit of being ascribed to errors 

 of observation. On the basis of these facts, the proportion 

 of oxygen in surface-water is sbown to depend not only 011 

 pressure and teniperature. hut. probably, also on the ef- 

 fect of one or more causes as vet unkhown. 



Wlien in\ istigating the degree in v.hich the proportion 

 of oxygen varies with the depth. it will be most convenieut 

 to express the difference. as a percentage of the total amount 

 of air. the absolute amount of air varying to a much greater 

 extent with- the teniperature than does its relative compo- 

 sition: besides. with tbis mode of expression considerably 

 less regard need be had to the influence of teniperature. 



If the tigures representing the results thus expressed 

 are arranged according to depth. the proportion of oxygen 

 present in the different strata will be found to exhibit very 

 considerable uniformity, as appears from tbe following Table. 

 based as it is on the whole series of determinations, with 

 tbe exception of two. the water with which the latter were 

 performed not having been boiled at once. hut allowed to 

 stand over for some time previous to examination. 



De enkelte Observationers Afvigeiser fra den ved 

 denne Tabel bestemte Regel ere i Betragtning af det under- 

 søgte Felts store Udstrækning hverken mange eller syn- 

 derlig store, idet kun lo. No. 2. 19. 38. 41». 64, 68. 83. 



Considering the great extent of the region investi- 

 gated, tbe deviation of the individual observations from tbe 

 standard given in this Table is neitber frequent nor con- 

 siderable. 10 onlv. viz. Xos. 2. 19. 38. 41». 64. 68. 83, 84, 



