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48
Ekman1 og Thorpe og Riicker2 har givet meget
fuldstændige Tabeller over Søvandets Volumina ved forskjellige
Temperaturer, hvorhos tillige ogsaa Dr. Karsten3 har
opstillet en Correctionstabel. hvorefter man kan reducere de
ved vilkaarlige Temperaturer aflæste Egenvægter til 17."5.
Sammenstiller man de Correctioner, som efter disse
Iagttagelser kunne beregnes, erholder man imidlertid især for
de lavere Temperaturer meget daarligt overensstemmende
Værdier, idet der kan optræde Differenter, der endog kan
overskride 0.0004. mellem de af Ekmann’s og Hubbard’s
Observationer beregnede Correctioner. hersker der den
største Overensstemmelse, men ogsaa her gaar
Different-serne paa enkelte Puncter op til meget nær 0.0001. I
Betragtning af disse tildels temmelig betydelige
Uoverensstemmelser mellem de hidtil publicerede Undersøgelser af
denne Art- kunde det ikke tindes ubeføiet endnu engang
at gjenoptage Bestemmelserne af Søvandets Volumina ved
forskjellige Temperaturer, og jeg besluttede mig derfor til
gjennem egne Undersøgelser at forvisse . mig om, hvilken af
de opstillede Tabeller der bedst svarede til Udvidelsen af
det i det norske Nordhav flydende Vand. Dels i dette
Øjemed dels for at bestemme de benyttede Aræometres
Correctioner og de Constanter, hvormed Chlorprocenterne
og Decimalerne i Egenvægten maatte multipliceres for at
give Saltmængden, har jeg anstillet Undersøgelser med
følgende Vandprøver.
Længde Dvbde
Station. Brt ddé. fra Grreenwich. Eng. Fvn. Meter.
2 45 68 0 21’ 2 " S’V. O 0
2 47 68 5-5 2 24 0. 500 . 941
253 Skjærstadfj ord. 0 O
254 f>7 27’ 13° 25’ 0 0
284 73 i I 2 58 O O
300 73 10 3 2’2 V. O 0
349 76 30 2 57 0. 1487 2719
362 79 59 5 40 . O 0
hvilke jeg for Kortheds Skyld i den Orden, hvori de
heltindes opførte, vil betegne med I. II o. s. v. indtil VIII.
Til Bestemmelse af Søvandets Udvidelse benyttede jeg et
Sprengel’s Pyknometer4, forarbeidet af to Stykker meget
tynde Glasrør af et og samme Rør med en indvendig
Diameter af omtrent 13""". Rørene vare nedentil
sammenlod-dede ved Hjælp af et snævert kort u-formig bøiet Glasrør
og oventil paaloddede knæformig bøiede solide Capillarrør
med meget fin Aabning. Ved Paalodningen af disse
Glasrør blev der saa meget som muligt draget Omsorg for, at
kun en liden Del af de videre Rør udsattes for
Opvarmning over Blæselampen, forat ikke Apparatet derved skulde
1 Kong]. Svenska Vetenskapsak. Handlingar 1*70 — 1.
2 Proc. Roy.Soc., 24 — 159.
3 Tafeln zur Berechnung der Beobachtungen an den
Kiistensta-tionen u. s. \v. Kiel 1874.
4 Pogg. Ann. 150 — 4.">9.
Ekman1, and Thorpe and Riicker2 having prepared
comprehensive Tables to show the volume of sea-water at
different temperatures; Dr. Karsten3, too. has published a Table
of Corrections by which specific gravities read at any
temperature may be reduced to 17."5. Meanwhile, on comparing
together the corrections computed from these observations,
the values obtained, more especially for low temperatures,
are found to agree but very indifferently, the difference in.
some cases exceeding even 0.0004. The agreement is
closest between the corrections computed from Ekman’s
. and Hul »bard’s observations; but here. too. the difference for
some temperatures amounts to very nearly 0.0001.
Considering. therefore, the want of uniformity, in some cases
very considerable, exhibited by such observations of this
kind as had till then been made public, it could not be
deemed superfluous to investigate anew by a further series
of experiments the variation in volume which sea-water
is found to undergo at different temperatures; and hence I
determined on ascertaining from the results of my own
observations which of the aforesaid Tables corresponded best
with the expansion of the water in the Norwegian Sea.
Partly with this object in view, and partly in order to
determine the corrections for the areometers and the
constants by which the percentages of chlorine and the
decimals of specific gravity had to be multiplied when
computing the amount of salt. I examined the following
samples of water: —
Station. Longitude Depth
Latitude. from Greenw. Eng. Fath. Metres.
245 68’ 21’ 2 " O O
247 68 5-5 2 24 E. 500 941
253 Tlie Skjærstad Fjord. O O
254 67° 27’ IS" 25’ O O
284" 73 i 12 58 O 0
300 . 73 10 3 22 W. O 0
349 76 30 2 57 E. 1487 2719
362. 79 59 5 40 O 0
which I will indicate, for the sake of brevity, by the Roman
numbers from I to VIII, and in the order in which they
are given here.- For determining the expansion of the
sea-water. I made use of Sprengel’s pycnometer;4 the
instrument was constructed of two pieces of glass tubing, cut ofl’
from the same length, with an inner (fiameter of about 13""".
These tubes were sealed together at their lower ends
by means of a short, narrow glass tube, bent into the fonn
of the letter U, and had strong knee-shaped capillary tubes
sealed on to their upper extremities. When sealing on
these glass tubes, the greatest care was taken to confine
the heat from the glass-blower’s lamp to as small a’ portion
1 Kongl. Svenska Vetenskapsak. Handlingar 1870. 1.
2 Proc. Roy. Soc., 24, p. 159.
1 Tafeln zur Berechnung der Beobachtungen an den
Kiistensta-tionen u. s. w. Kiel 1874.
4 Pogg. Ann. 150, p. 459.
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