1. Om Luften i Sovamlet. 
1. On tin* Air in Sea- Water. 
A llerede i lange. Aarrækker har der fra Tid til anden af 
forskjellige Ckemikere været foretaget Experimenter i 
den Hensigt-at studere Forholdene ved den atniosphæriske 
Lufts Absorbtion af de Vædsker, hvormed den i Naturen 
kommer i Berøring, men det er dog først i de seneste Aar, 
at dette Spørgsmaal har været gjort til Gjenstand for mere 
omfattende Under søgelser. hvad angaar Søvandet i de aabne 
Have. Rigtignok foreligger der ogsaa fra ældre Tider en- 
kelte Opgaver over Sammensætning og Mængden a f den i 
Søvandet opløste Luft, men disse ere for det Meste bundne 
til nogle ganske faa Puncter af Kysterne. og der. hvor 
Forsøgene ogsaa pmfatté Vandpirøver fra det aabne Hav, 
er der ofte saameget at indvende mod Materialets Indsam- 
ling og Opbevaring, at man. selv om Intet maatte være at 
udsætte‘paa Metboderue til dets Undersøgelse, ikke kunde 
sætte disse i Klasse med de med vore Tiders fuldkomnere 
Hjælpem idler udførte Observat ioner. 
•Naar saaledes vort Kjendskab til Fordelingen af Luf- 
ten i Verdenshavene specielt for de store Dybs Vedkommende 
lige til de seneste Aar maa siges at have været meget 
mangelfuldt, da maa Grunden hertil søges i de mange Van- 
skeligbeder. som man allevegne møder, naar man vil under- 
age disse Spørgsmaal. Hvor det gjælder at bestemme 
Sammensætn ingen af den atniosphæriske Luft. giver Luftens 
Letbevægelighed Ret til af Undersøgelser udførte paa faa 
Puncter at slutte til den hele Atmosphære. hvad der imid- 
lertid ikke er Anledning til for Søvandets Vedkommende. 
Der fordrer Havenes langt ringere Bevægelighed et større 
Antal Observationer. idet der her maa stilles meget stren- 
gere Fordringer til den geografiske Udbredning. Enten 
maatte altsaa Vandprøver hjemføres fira fjerne Farvande, 
saaledes at de ved en længere Tids Henstand udsatte for 
allebaande fremmed Indvirkrring kunde blive, aldeles ubrug- 
bare, eller Analytikeren maatte. udsat for alle de Ulemper, 
som et Skibs Bevægelser medfører for vidensknbelige Un- 
dersøgelser, forsøge bedst muligt at udføre sine Observatio- 
ner ombord. Men selv naar der hos mange Chemikere fra 
ældre Tider kan have været Interesse for ved Undersøgel- 
Deu norske Nordliavsexpedition. Tornøe: Cliomi. 
E xperiments have long since been instituted, from time 
to time, by divers chemists, with the object of investi- 
gating the absorption of atmospheric air by the fluids with 
which in the course of nature it comes in contact ; but not 
till of late years has this phenomenon been made the subject 
of exhaustive treatment in its relation to ocean- water. 
True, there do exist comparatively early statements respect- 
ing the amount and composition of the air present in sea- 
water. but the great majority of such are confined to a 
very few coastal* localities; and when, as was sometimes the 
case, the samples of sea-water examined had been drawn 
from the open sea, the mode of collecting and preserving 
them was frequently so open to objection that, even assum- 
ing the methods adopted for their examination to have 
been in every respect trustworthy, these early experiments 
will not bear comparison with those of modern date, per- 
formed with the far superior apparatus since devised. 
Our knowledge therefore, till but a few years since, 
of the distribution of air in ocean-water, must be said 
to have continued very imperfect; and the reason is 
found iii the numerous difficulties everywhere encountered 
when proceeding to investigate so intricate a subject. From 
the great mobility of the atmosphere, experiments in a few 
localities only will suffice to determine the general com- 
position of air; but with sea -water the case is different. 
Water being far less fluid than air, many observations 
are obviously needed, since the greatest importance 
must be attached to geographical position. Hence, sam- 
ples of sea-water had to be brought home from 'distant 
regions, and in that case, by being allowed to stand over 
for a comparatively long period, left exposed to all manner 
of disturbing influences : or the observations were taken on 
board, and experiments performed to the best of the ana- 
lyst's ability, in spite of the numerous drawbacks entailed 
by the motion of the vessel. But, though many of the 
earlier chemists would, when at sea, no doubt have felt an 
interest in contributing tø solve the problem of the distri- 
bution of air in the water of the ocean, they almost inva- 
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