22 



liggende Lag skulde kunne hidføre en anden Fordeling af 

 Luften end den. der allerede existerer fra den Tid. da 

 Våndet sidste Gang befandt sig i Overfladen udsat for fri 

 Paavirkning af Atmosphæren. Luften vil saaledes kun 

 gjennem Våndets Circulation kunne naa ned i Dybet, og 

 nogen Udjevning af Luftmængderne vil der kun kunne ske 

 gjennem Blanding af de forskjelligartede Vandmængder, en 

 Blanding, som under Forudsætning af at der ikke ogsaa 

 foregaar Opvarmning eller Afkjoling. ikke vil kunne for- 

 rykke det rette Forhold mellein Temperatur og Kvælstof- 

 mængde. da Kvælstofmængdens Variation med Temperatu- 

 ren fremstilles ved en ret Linie. 



Man vil altsaa, dersom disse Forudsætninger holde 

 Stik. ved en Kvadstofbestemmelse i de dybere liggende 

 Vandlag kunne om end meget raat bestemme, om disse 

 have været Gjenstand for en væsentlig ( ►pvarmning eller 

 Afkjoling, siden de sidst befandt sig i Overfladen, forudsat 

 at man kan negligere Virkningerne af Atmosphæretrykkets 

 Forandringer og andre mulige Tilfældigheder. som under 

 Absorbtionen i Overfladen vil kunne gjøre sin Indtlydelse 

 gjældende. 



Grupperer man de her offentliggjorte Observationer 

 efter Vandprøvernes Temperatur, viser det sig. at Kvæl- 

 stofmængden meget uøie svarer til den etter denne Tempe- 

 ratur af Formelen beregnede, det vil sige. Vandprøvernes 

 Temperatur skulde ikke i væsentlig Grad have forandret 

 sig, siden de sidst befandt sig i Overdåden. Man faar 

 nemlig : 



At Overensstemmelsen for Temperaturerne under 0° 

 ikke er saa fuldstændig som ellers, skyldes ogsaa her de 

 ovenfor nævnte ;"> Observationer alle udførte paa Togtet i 

 1877. Beregner man derimod den midlere Temperatur og 

 Kvælstofmængde for dette Interval af di' paa sidste Aars 

 Togt gjorte Observationer, erholder man til Middeltempe- 

 raturen -1.2 Kvælstofmængden 14.59 CC. altsaa kun 

 0.09 CC. mindre end beregnet. 



Benyttes paa samme Maade de af Dr. Jacobsen of- 

 fentligjorte Observationer til et Overslag over Kvælstof- 

 mængden i Nordsøen, erholder man med runde Tal: 



the surface causing a distribution of the air different to 

 that which existed when the water was last at the surface. 

 in direct contact with the atmosphere. Hence the air 

 cannot penetrate to such depths save by the circulation 

 of the water, and an adjustment of the amounts of air can 

 be effected solelv by the mixing of the water different in 

 composition. which will not. however. unless we assume 

 a siinultaneous increase or decrease of heat. disturb the 

 true relation bétwe^n the temperature and the amount of 

 nitrogen, since the variation of the latter with the temper- 

 ature is expressed by a right line. 



K, then. these assiimptions are found to hold good. 

 it will be possible. when computing the proportion of nitro- 

 gen in the lower strata of the water, to determine — very 

 roughly indeed — whether the latter have experienced 

 a ny increase or decrease of heat since thev were last at 

 the surface. provided we can ignore the effect of change 

 in the atmospheric pressure and of other accidental circum- 

 stances, which. during the process of absorption, may have 

 made their intluence felt. 



On grouping together according to the temperature 

 of the samples of water examined, the observations published 

 in this Memoir, the proportion of nitrogen will be found 

 to agree very closely with that computed by the formula. 

 showing. as appears from the following Table. that the 

 temperature could have varied but little since the water 

 bad been last at the surface. 



For. the temperatures under 0° the agreement is in- 

 deed not so close: but here. too, the cause may be traced 

 to the aforesaid 5 observations from the voyage in 1 s 7 7 . 

 If, however. we conipute the mean temperature and the 

 amount of nitrogen for that interval by the results of the 

 observations instituted on the last voyage, the mean tem- 

 perature will be — 1.2 and the amount of nitrogen 14. "i 1 . 1 . 

 or only 0.09" less than that computed by the formula. 



A similar computation with the observations published 

 by Dr. Jacobsen tor estimatmg the amount of nitrogen in 

 the water of the North Sea. will give. in round numbers. 

 the following results: — 



