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ser paa Reiser at give Bidrag til Løsningen af
Spørgsmaalet om Fordelingen af Luften i Havet, da har
Anledningen dertil næsten bestandig manglet. Først ved de i
de senere Tider hyppigt* udsendte Expeditioner, hvormed
der har været givet Chemikere Anledning til at medfølge,
har det været muligt mere detailleret at studere disse Ting.
Ved disse Expeditioner ’har Formaalet udelukkende været
videnskabelig Cndersøgelse af Havet, og der har derfor
med Hensyn paa Udrustningen, altid været lagt megen Vind
paa ved hensigtsmæssige Foranstaltninger og omhyggelige
Forberedelser at fremme dette Formaal saa meget som
muligt, og det er derfor klart, at disse Expeditioner maa
have den største Betydning for den chemiske Undersøgelse
af Havene specielt, hvor Talén er om saadanne
Observationer, der ligesom Bestemmelser af Gasarterne. ikke taale
Opsættelse, men nødvendigvis maa udføres øieblikkéli’g efter
at Vandprøven er øst. Saaledes maa aabenbart de under
disse Omstændigheder udførte Observationer faa størst Vægt,
hvor. det dreier sig 0111 at skaffe Oplysninger om Gasarterne
i Søvandet, udenat det clog derfor vil tindes paa urette
Plads her at give en kort Oversigt ogsaa over de herover
udførte ældre Undersøgelser.
De tidligste Undersøgelser, der mig bekjendt ere
gjorte over Luften i Søvandet, udførtes i 1838 af Fremy1
paa nogle Vandprøver, der over et Aar forud vare bleven
optagne paa den franske Expedition med • La Bonite’ i 1836
og 37. Vandprøverne bestode dels af Overfladevand dels
af Vand fra forskjellige DVb indtil ’450 franske Favne og
vare optagne med et af Biot opfundet Apparat.-
A’ed Analysen af den udkogte Gas absorberede Fremy
Kulsyren med Kalilud og Surstoffet med Phosphor.
Resultatene ansaaes allerede af Fremy selv for upaalidelige og
de staa saa bestemt i Strid med alle nyere Angivelser, at
man med temmelig stor Sikkerhed kan antage, at det lange
Tidsrum mellem \ andprøvernes Øsning og deres
Undersøgelse har gjort dem fuldstændig ubrugbare«
I 1843 udførte Morren3 nogle Undersøgelser af
Overfladevandet ved Saint-Malo nærmest i den Hensigt at paa-
vise Sollysets Indflydelse paa den relative Sammensætning
af den af Vandet absorberede Luft. Han kom i den
Henseende til det Resultat, at Surstofmængden fandtes størst
og Kulsyremængden mindst ved klart Sollys, hvorimod om-
vendt Surstofmængden fandtes mindst og Kulsyremængden
størst ved mørkt overskyet Veir. Vandprøverne undersøg-:
tes ikke paa Stedet, men sendtes til Rennes, hvor de af
Morren udkogtes i Kolber paa 4.5 Litre. Den udkogte Gas
lededes gjennem Kautschukledning over i en Flaske, hvori
Gasarterne opsamledes over Vand. Ved Analysen 5af Gasen
anvendte han til Absorbtion af Kulsyren Kalilud og for-
1 Compt. rend. (i—(il(i.
2 Pogg. Ann. 37 — 416,
3 Ann. Chim. Phys. [3] — t’j — :>.
riably lacked the means. Not till chemists "had been sent
out on the numerous ’Expeditions dispatched of late years
to all quarters of the globe, was it possible to study this
subject in detail. The sole object of such Expeditions
having been the scientific investigation of the,ocean, they were
naturally fitted out with the greatest possible care, being
furnished with the latest and most improved apparatus,
and every necessary aid and appliance. It is obvious,
therefore, that these Expeditions must largely contribute
to our chemical knowledge of the ocean, more
particularly with regard to’ observations which, like the
determination of gaseous bodies, will not brook delay, but
must be taken immediately the sample of water has been
drawn. Hence, very great weight should be attached to
observations instituted under such circumstances, viz. those
that relate to the determination of gaseous bodies in
sea-water. It will not. however, be out of place, briefly to noticé
some of the earlier observations undertaken with that
object in view.
The earliest experiments, so far as I am aware,
relating to the air in .sea-water, were instituted in 1838, by
Fremy,1 with samples of water drawn more than a year
before on the French Expedition with the ’Bonite.’ in 1836
and 1837. These samples of water consisted partly of
surface-water. partly of water from various depths, the great-*
est being 450 French fathoms; and were collected with an
apparatus devised by Biot.-
When analysing the gas driven off. the carbonic acid
was absorbed in a lye of potash, the oxygen being
consumed with phosphorus. But Fremy himself did not regard
as trustworthy the results of this process; and they have
proved so decidedly at variance with those of all later
observations, that his samples of water, owing to the length
of time for which they had been preserved previous to
examination, had no doubt become utterly worthless for
experimental purposes.
In 1843. Morren3 instituted a series of experiments
with surface-water, near St. Malo, .chiefly with the object
of determining the influence of solar light on the
composition of the air absorbed by sea-water. He found the
proportion of oxygen to be greatest, and that of .carbonic acid
least, in bright weather; whereas the proportion of oxygen
was least, and that of carbonic acid greatest, with a dark,
cloudy sky. The samples of water were not examined
on the spot, but taken to Rennes, and there boiled by
Morren, in matrasses containing 4.5 litre. The gas driven
off during the process was conducted through . a
caou-tschouc tube into a phial, and there collected over
water, When analysing, the gas, Morren used a lye of
1 Compt. rend. <>. p. (iHi.
2 Pogg. Ann. 37, p. 4 Hi.
* Ann. Chim. Phys. [3], 12, p. 5.
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