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58
rimeligst bliver at tilskrive Observationsfeil. Som
Chlor-coefficient knu heraf opstilles
1.809 + 0.00070
med en sandsynlig Feil af en enkelt Bestemmelse af + 0.002
og som Egenvægtscoefficient
131.9 + 0.058
med en sandsynlig Feil af en enkelt Bestemmelse af + 0.15.
Disse Værdier stemme især for Chlorcoefficientens
Vedkommende ganske vel overens med tidligere fundne
Værdier, saaledes har baade Forchhammer og Ekman i
Middel fundet 1.811. medens de af Andre opstillede
Egen-vægtscoefficienter overalt ere noget mindre end den af mig
fundne.
Ved Hjælp af disse Coeflicienter har jeg af de paa
Expeditionen Togter udførte Chlor- og
Egenvægtsbestem-melser beregnet Vandprøvernes Saltgehalt og sammen med
Originalobservationerne opført dem i nedenstaaende Tabel.
Egenvægterne ere i Regelen kun aflæste med 4
Decimaler. clet 5te er kun opført, hvor det havde en Værdi nær
5, saa at det kunde være Tvivl underkastet, om der ved
Afrunding skulde formindskes eller forhøies. I de
reducerede Egenvægter findes ligeledes kun opført 4 Decimaler,
hvor det uden Tvivl kunde afgjøres, til hvilken Side
Afrundingen skulde finde Sted. hvorimod der i modsat
Fald ogsaa der er tilføiet et 5te. De med * betegnede
Egenvægter ere aflæste paa Aræometre, hvis Correction
ikke er bleven bestemt. Til Optagelse af de til
Undersøgelse af Saltholdigheden bestemte Vandprøver er foruden
det tidligere beskrevne, af Wille construerede. Apparat
ogsaa paa grundere Vand ofte benyttet den af Ekman
angivne fortrinlige Vandhenter, som imidlertid ifølge den
Fremgangsmaade, hvorefter Dyblodninger paa den norske
Expedition foretoges, ikke egnede sig til Brug ved større Dyb.
Ved Velvillie af Professor Mohn har jeg faaet
opgivet de undersøgte Vandprøvers Temperatur i Havet,
hvorved det er bleven muligt ogsaa at tilføie en Rubrik for
deres Egenvægter ved denne Temperatur i Forhold til
rent Vand af 40.1 Af« de i Tabellen gjengivne
Observationer ere alle indtil No. 149 udførte paa 1ste Togt af
Svendsen, alle fra 149 til 225 paa 2det Togt* af mig, de
øvrige ere udførte paa sidste Togt af Schmelck og mig i
Fællesskab, saaledes at det største Antal skyldes Schmelck,
der dette Aar medfulgte Expeditionen.
and hence the variation in the results should most
probably be ascribed to errors of observation. The coefficient
of chlorine- may accordingly be taken at —
1.809 + 0.00076
with a probable error in a single determination of + 0.002,
and the coefficient of specific gravity, at —
131.9 + 0.058
with a probable error in a single determination of+0.15.
These values agree closely, in particular as regards
the coefficient of chlorine, with those previously found.
Thus, for instance, the mean value found both by
Forchhammer and Ekman was 1.811, whereas the coefficient of
specific gravity given by former observers is somewhat
lower than mine.
By means of these coefficients I have computed from
the determinations of chlorine and specific gravity the
amount of salt in the samples of water collected on the
Expedition, and have set down the observations and their
results in the accompanying Table, which calls for a brief
explanation.
The specific gravities are as a rule not read to more
than 4 decimals, a fifth being added only in the event of
its having a value of 5. in which case it is often doubtful
whether, when rounding off the figures, there should be
increase or diminishment. The reduced specific gravities, too.
are expresed with 4 decimals only, wherever it was
manifest in-which direction the rounding off bad to be made:
when such is not the case, a fifth has been added. An
asterisk at the side of a specific gravity denotes that the
latter was determined with an areometer for which no
correction had been found. Besides the instrument devised
by Wille, of which a description has been given, Ekmans
excellent apparatus was likewise made use of. in
comparatively shallow localities, for collecting the Rumples of
sea-water in which to determine the amount of salt; the mode
of sounding practised on the Norwegian North-Atlantic
Expedition would not admit of its adoption for greater depths.
Professor Mohn has kindly furnished me with the
temperatures of the samples of water in situ, which has
enabled me to give an aditional column for the specific
gravities at those temperatures as compared with pure
water of 4". 1 Of the observations given in the Table,
those extending from No. 1 to No. 149 were performed
on the first voyage, by Mr. Svendsen; those extending from
No. 149 to No. 226, on the second voyage, by myself; the
remainder were taken on the last voyage, by Mr. Schmelck
and myself conjointly, the greater number, however, by Mr.
Schmelck, who that year accompanied the Expedition.
1 Rent Vand af 4° er ved denne Reduction valgt som Enhed,
fordi den allerede tidligere er anvendt af J. Y. Buchanan (Proc.
Roy. Soc. 24—597). Ved Beregning af Egenvægternes Værdi
ved Havets Temperatur i Forhold til Vand af 4° er
Forholdet mellem Volumet af rent Vand ved 4° og 17.°.’) sat = 0.998708.
1 Pure water of 4° was chosen as the unit of reduction, J. Y.
Buchanan having previously adopted it as such (Proc. of Roy.
Soc. 24, p. 597). When- computing the specific gravities at the
temperature of the sea, as compared with water of 4°, the
ratio existing betweeu the volume of pure water at 4° and 17.°.">
was assumed to be 0.998768.
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