Full resolution (JPEG) - On this page / på denna sida - Sidor ...
<< prev. page << föreg. sida << >> nästa sida >> next page >>
Below is the raw OCR text
from the above scanned image.
Do you see an error? Proofread the page now!
Här nedan syns maskintolkade texten från faksimilbilden ovan.
Ser du något fel? Korrekturläs sidan nu!
This page has never been proofread. / Denna sida har aldrig korrekturlästs.
Paafyldningen af Flaskerne, blev der anvendt deü største
Omhyggelighed, idet disse Operationer enten foregik under
Opsigt af Hr. Tornøe. der fra 1877 var ansat som
Expeditionen Kemiker, eller af mig. der i det følgende Aar
deltog i Expeditionen, da Hr. Tornøe ikke alene kunde
overkomme alle de kemiske Arbeider, som vare nødvendige
under Reisen. De af os medbragte Vandprøver ere
hentede nordenfor den nordlige Polarkreds; de øvrige, der ere
tagne söndenfor denne, ere paa samme Vis indsamlede og
opbevarede af Hr. Svendsen, der var Expeditionen
Kemiker paa dens første Udflugt i 1876.
’ Alle de Arbeider, der ere udførte ombord, saasom
Luftudkogninger. Bestemmelser af Kulsyren. Klormængden
og den specifiske Vægt ere senere bearbeidede og
diskuterede af min Ven Hr. Tornøe, der har overtaget den
fysiskkemiske Del af Arbeidet, medens det for mig stod tilbage
at underkaste de medbragte Vandprøver en kemisk Analyse
med Hensyn til de øvrige faste Bestanddele.
Ved disse Undersøgelser har jeg nu sat mig * som
Formaal at udfinde, hvorvidt Forholdet mellem Søvandets
Bestanddele er udsat for saa store Forandringer, at de
lader sig paavise ved de nøiagtigste analytiske Methoder,
og om man af de fundne Tal kan uddrage nogen Regel
med Hensyn til de mulige Forskjelligheder i Søvandets
Sammensætning.’ I dette Øiemed har jeg udelukkende lagt
Vægten paa de af Havets Bestanddele, der. for det første
lader sig bestemme med den største Lethed og Sikkerhed,
og for det andet — efter al Erfaring .og Sandsynlighed —
maa være de Stoffer, som fortrinsvis kan paavirkes af andre
i Havet forekommende Kræfter. Med dette Formaal for
Øiet maa man nærmest henvende sin Opmærksomhed paa
Kalk. Magnesia, Svovlsyre og Klor. Natron. Kali og de
i mindre Mængde forekommende Baser og Syrer har
med Hensyn til det foreliggende Spørgsmaal liden eller
ingen Interesse, da de ikke kan bestemmes med den
nødvendige Nøiagtighed. Hellerikke kan man for Alkaliernes
Vedkommende tænke sig, at de skulde være synderlig
afhængige af fremmede Paavirkninger, uden forsaavidt som
en Variation i Klornatrummængden, der jo udgjør den
overveiende Del af Havsaltet, vilde være ensbetydende med
en tilsvarende Forandring i Vandets Egenvægt. Da der
imidlertid er stor Uoverensstemmelse mellem de Tal, der
af forskjellige Kemikere er fundne for Kalimængden i
Søvandet, har jeg for Sammenlignings Skyld bestemt denne
Bestanddel i nogle Vandprøver fra forskjellige Punkter af
Havet.
Blandt de Salte, der forekomme i mindre Mængde i
’ Søvandet, har isærdeleshed den kulsure Kalk været
Gjenstand for Kemikernes Opmærksomhed. Mange har bestemt
denne Forbindelse ved at koge en vis Portion af Søvandet
i længere Tid — under stadig Erstatning af det
fordampede Vand — og derpaa veie det udskilte Bundfald. Ved
at analysere dette har jég imidlertid ikke fundet Spor af
vised by Captain Wille. R. N. When drawing the water
and filling the phials, the greatest care was taken, these
simple but delicate operations having been invariably
performed in the presence either of Mr. Tornøe (since 1877
chemist to the Expedition) or of myself, who the following
year went out as assistant-chemist. Mr. Tornøe not being
equal to all the chemical work that had to be dpne on the
last cruise. The samples of sea-water brought home by us
on the return of the Expedition, were all collected north
of the Arctic circle: those from the first cruise, in 1876.
having been similarly obtained and preserved by Mr.
Svendsen. the gentleman originally appointed chemist to the
Expedition.
All. chemical work done on board, viz. determinations
of air. carbonic acid, chlorine, and specific gravity, has been
since, critically reviewed and tested by my friend Mr.
Tornøe, who undertook to work up’ the physico-chemical
details, while I have analysed the various samples of
sea-water with a view to determine their solid
constituents.
My object with this investigation, has been to
ascertain, if possible, whether the relation subsisting between
the component parts of sea-water varies sufficiently to admit
of determining its fluctuations by the most exact analytical
methods: and whether, in that case, it were not possible
from the results attained to deduce some definite rule
regulating such assumptive differences in the composition of
sea-water. To this end. I have exclusively laid weight on
those constituents of ocean-water which, first, admit of being
determined- with the greatest accuracy and facility, and
which, secondly, — as is indicated alike by experience and
probability, — must be the substances specially acted upon
by the forces operating in sea-water. And those substances
are chiefly lime, magnesia, sulphuric acid, and chlorine.
Soda, potash, and the bases and acids occurring in
quantities comparatively small, have, as affecting this question,
little or no interest, since they cannot be determined with
sufficient exactness. Nor is it likely that the proportion
of alkalies is dependent in any considerable degree upon
extraneous influence, save inasmuch as a variation in the
amount of chloride of sodium, which constitutes, we know,
by far the greater part of the salts in sea-water, would
imply a corresponding change in the specific gravity of
the water. Meanwhile, as the figures computed by divers
chemists for the proportion of potash in sea-water, exhibit
a remarkable want of agreement. I have determined that
substance in several of the samples of water collected from
different parts of the.ocean.
• Among the salts which séa-water contains in small
quantities only, carbonate of lime is that which has most
attracted the attention of chemists. Its relative proportion
has been repeatedly determined, by boiling for a
considerable time a given quantity of sea-water. — the loss from
evaporation being supplied as it arises. — and then
weighing the precipitate. On analysing this deposit. tI have
<< prev. page << föreg. sida << >> nästa sida >> next page >>
