29 Torbjørn Gaarder 
formel for opløseligheten av surstof i sjøvand av temperatur = t° 
og klorgehalt = Cl °/oo y»from a free dry atmosphere of 760 mm. 
pressure“ er: 
O. = 10,291 — 0,2809 - t + 0,006009 - t? — 0,0000632 - t* 
— [0,1161 — 0,003922 - t + 0,000063 - t?] CI. 
Ved hjælp av formelen er den tabel beregnet som findes gjen- 
git bl. a. i HertanD-HANsEn: ,,The Ocean Waters* II. Denne ta- 
bel er utarbeidet efter opdrag fra den Internationale Kommission 
for Havundersokelser, og er vel saa rigtig som den av JACOBSEN 
opstillede. Fox gjør ogsaa selv opmerksom paa dette. Han sier 
(1. e. 8. 19) ,He (d.e. JACOBSEN), in his determination, placed a 
quantity of water in a large bottle and rotated it, by means of a 
motor, with its axis horizontal, until determination by means of the 
well known WINkLER's titration method, showed a constant Oxy- 
gen value. As a matter of fact there is a theoretical objection to 
the adoption of this method which must not be overlooked. If 
this metod be employed at all, it is necessary to ensure very ef- 
ficient circulation between the air in the bottle and de outside air, 
because the partial pressures of the Oxygen and Nitrogen within the 
bottle will otherwise alter. Oxygen is in fact twice as soluble as 
Nitrogen: and the result is that its original proportion in the air 
inside the bottle will be diminished and that of the Nitrogen will 
be increased by shaking with water, unless the air be continually 
renewed all the time. As pointed out above, the gas-phase as well 
as the liquid-phase should always be analysed when employing 
these methods. It may be expected that this method would give 
too low values for Oxygen and too high values for Nitrogen As 
matter of fact this is just what the present writer found in using 
a method similar to that of JACOBSEN, in connection with some 
other work. If water be saturated with air in this way and then 
analysed, it is always found that the Nitrogen indicates a tempera- 
ture lower than that of the saturation temperature and the Oxygen 
a higher temperature; but that if a current of air be drawn through 
the bottle (by means of a water-pump) while the bottle is rotating, 
that this apparent temperature-difference found, tends to disappear.. 
It appears that in Jacospsrn’s determinations, there was no 
particular arrangement for the renewal of the air; to that extent 
the values may be expected to be low, and by a nearly constant 
percentage for different waters and temperatures, which might 
