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Da jeg Vaaren 1877 blev opfordret til at overtage
disse Arbeider, var der kun givet mig faa Dages Varsel,
saaat jeg havde de største Vanskeligheder med at faa
udfort selv de aller nødtørftigste Forberedelser, og naar det
alligevel lykkedes at faa Alt tilfredsstillende ordnet før
Aireisen, da skyldes dette udelukkende den Beredvillighed,
hvormed Hr. Professor Waage bistod mig blandt Andet
ogsaa med Indredningen af det chemiske Laboratorium ombord.
Det paa Expeditionens første Togt i 1876
fremherskende ualmindeligt stormfulde Veir gjorde det i høi Grad
vanskeligt ja næsten ugjörligt at udfore de chemiske
Observationer ombord, og det Udbytte, som af Svendsen hjembragtes
fra første Togt, indskrænkede sig derfor i clenne Branche til
17 Luftprøver, hvoraf desuden 3 ved Uheld senere gik tabt.
Det rolige Veir. som de to sidste Aar begunstigede
Expeditionens Arbeider, tillod mig derimod paa de Togter,
hvormed der var givet mig Anledning til at medfølge, at
indsmelte et større Antal, idet der for disse Aars
Vedkommende erholdtes 80 Luftbestemmelser af de hjembragte
Luftprøver, hvoraf 9 vare indsmeltede af Hr. Schmelck.
Naar Udbyttet ikke er blevet større, da har dette sin Grund
i. at talrige Observationer gik tabt nogle faa ved Uheld
under Analysen men de fleste ved Uheld under
ludsmeltningen. Saaledes var der til Brug paa sidste Togt fra
Küchler & Söhne i Ilmenau sendt mig nogle
Luftopsam-lingsrør. hvoraf over 75 °/0 tiltrods for den omhyggeligste
Behandling sprang enten under Indsmeltningen eller efter
samme. Luftprøverne ere alle analyserede ved det af
Franckland og Ward1 angivne Gasanalyseapparat, saaledes at
Kulsyren er fjernet med Kalilud og Surstoffet bestemt ved
Forbrænding med Vandstof. De 14 førstnævnte Prøver
ere analyserede af Hr. Svendsen de øvrige 80 af
Forfatteren. De erholdte Resultater tindes sammenstillede i
Tabel I, hvortil kan bemærkes følgende: De i Tabellen
opførte Temperaturangivelser ere mig meddelte af
Professor Mohn. Ved Angivelse af de Dybder, hvorfra
Vandprøverne ere hentede, er ikke taget Hensyn til. at
Vand-henteren først lukker sig efter circa 7 Favnes Indhivning.
Ved de med * betegnede 10 Nummere var der i de til
Luftprøvernes Opbevarelse benyttede Glasrør smaa Feil.
uden at jeg dog har fundet mig foranlediget til at tillægge
disse mindre Vægt end de Øvrige, da man vel ikke kan
tænke sig Muligheden af en Lækage^ uden at den. naar
Glasrørene i flere Maaneder opbevaredes under en
Tryk-d i ff ei’ents mellem det ydre og indre Gastryk af circa 300
til 400mm, maatte have øvet en mærkbar Virkning paa den
indesluttede Lufts Sammensætning. Jeg kan saa meget
trøstigere tage dem meel i Beregningerne, hvor det gjælder
at opstille de almindelige Slutninger, som de ikke i
synderlig Grad ville bidrage til at forrykkç Udseendet af de
endelige Resultater. Alle Gasvolumina tindes i Tabellen
udtrykte i CC. per Litre udkogt Søvand reduceret til 0° og
760mm Barometerstand.
When, in the spring of 1877. I was requested to
undertake these labours, I had but a. few days’ notice, and
experienced, therefore, very great difficulty in making
even the most necessary preparations: nor would it indeed
have been possible to get everything satisfactorily arranged
in so short a time but for the readiness with which
Professor Waage’ came forward to assist me; for instance, in
fitting up the chemical laboratory on board.
The exceptionally heavy weather on the flrst cruise
in 1876. rendered it in the highest degree difficult, nay
well nigh impracticable, to perform the necessary
experiments on board; and hence the chemical work done by
Svendsen on the first voyage was. with regard to
gas-determinations, confined to collecting 17 samples of air, 3 of which
however were subsequently lost. On the two last cruises of
the Expedition the weather proved much more favourable,
aud I succeeded in obtaining a larger number of samples
(9 of them collected by Mr. Schmelck), with which, when
brought home, 80 air-determinations were performed. A more
satisfactory result would, however, have been obtained but
for the loss of numerous samples, some few from accident
when analysing the gass, but the great majority by reason
of the difficulty experienced in sealing. Thus, for instance,
on the last voyage 75 per cent of the glass tubes for
collecting air, procured from Küchler & Sohne in
Ilmenau, notwithstanding the greatest care cracked either
during the sealing-process or after its completion. The
samples of air were all of them analysed in the apparatus
described by Franckland and Ward.1 the carbonic acid
having been absorbed in a lye of potash and the oxygen
determined by consuming it with hydrogen. The first 14
samples were analysed by Mr. Svendsen, the remaining 80
by myself. The results obtained will be found in Table I.
The temperatures in the Table were given by Professor
Mohn. When stating the depths from which the samples
of water were drawn, regard has not been had to the fact,
that the instrument used for collecting them does not close
till it has been hauled in about 7 fathoms. The asterisk
marking 10 of the determinations signifies that the glass
tubes used for preserving these samples of air had small
defects. To these determinations, however, I have not attached
less weight than to the others; for it is impossible to
conceive that a leakage, after the glass tubes had been exposed
for months together to a. difference of pressure amounting
to 300mm—400’"’", viz. that existing between the air inside
and the atmosphere without, should not have had an
appreciable effect on the composition of the air they contained.
’ Moreover, I hesitate the less to include them as factors
when seeking to arrive at general conclusions, since
they cannot to any considerable extent disturb the
character of the final results. The volumes are given in
cubic centimetres per litre of the sea-water examined,
reduced to a temperature of 0° and a pressure of 760mm.
1 Chem. Soe. Journ. 22—313. 1869.
1 Chera. Soc. Journ. 22, p. 313; 1S69.
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