29 
ikke ved fortsat Inddampning skulde kunne have erholdt 
et større Udbytte af Kulsyre. De af Dr. Jacobsen og 
J. Y. Buchanan udførte Observatiouer kunde derimod ikke 
saa ligefrem forkastes, idet der jo kunde tænkes Muligked 
for, at det ved de af dem benyttede Methoder kunde have 
lykkedes ved den langvarige Kogning at uddrive ogsaa al 
neutralbunden Kulsyre. i hvilket Fald de af dem opførte 
Tal i en anden Henseende kunde faa Betydning nemlig 
som Udtryk for den samlede Sum af den i Sø våndet inde- 
holdte Kulsyre. 
Desværre lagde dere Omstændigkeder Hindringer i 
Veien for Afslutningen af mine Forsøg over disse Gjen- 
stande i Vinteren 1877 — 78, dels var min Tid optagetmed 
andre Arbeider, dels lod min Helbred den største Del af 
Vinteren adskilligt tilbage at ønske, saaat mine Forsøg in- 
genlunde liavde den ønskelige Fremgang, og jeg blev der- 
for nødt til at gaa ud ogsaa paa Togtet i 1878 uden nogen 
paalidelig Methode til Bestemmelse af den i Søvandet inde- 
lioldte Kulsyre. Da jeg efter endt Togt om Høsten vendte 
tilbage, gjenoptog jeg imidlertid atter mine Undersøgelser 
og bragte dem til Afslutning. 
Gjehnem en netop da af C. Rorchers offentliggjort 
Afhandling 1 om Bestemmelsen af Kulsyren i naturlige Mi- 
neralvande blev jeg gjort opmærksom paa det for Bestem- 
melse af Kulsyren i Carbouater af Alexander Glassen angivne 
Apparat,- som jeg senere i stor Udstrækning har benyttet. 
Apparatet i den Form, hvori det her er kommen til 
Anvendelse, tindes sammenstillet i Figur 3. 
A er 2 med Natronkalk fyldte uformige Rør, B inde- 
holder Barytvand. C er en Erlenmeyers Kolbe paa circa 
0.5 Litre, der gjenuem et ved Bunden udmundende Rør 
communicerer m,ed B, medens et lige under Kautschuk- 
proppen udmundende sætter den i Forbindelse med Kjøle- 
leren D, hvis indre Del efter Glassen bestaar af et 27 — 
30 mm vidt Glasrør. hvortil i øvre og nedre Ende er loddet 
Rør med respective 15 og 'l mm Diameter. Forlaget E er 
fuldstændig af samme Construction som det af Jacobsen 
benyttede og er oventil forsynet med det af P. Wagner 3 
foreslaaede med Glaskugler fyldte Rør F. 
Ved a, hvor cler tindes en Indsnevring, er anbragt 
en noget større Glaskugle, som temmelig nøie dækker pver 
det nederste snevre Rør. Idet det til Opsamling af Kul- 
syren anvendte titrerede Barytvand heldes ned gjennem F, 
.fjernes Proppen b, indtil det Meste af Barytvandet har 
passeret a, men sættes derpaa hurtigt i, saaledes at der 
over de nederste Glaskugler bliver staaende noget Baryt- 
vand til en Høide af omtrent 50 mm over a. Dersom nu 
series of observations instituted by Dr. .lacobsen and J. Y. 
Buchanan cannot however be wholly rejected, since the 
protracted boiling characteristic of the method they adopted 
may possibly have driven otf all the carbonic acid contained 
in the carbonates, in which cast* their figures would acquire 
importance as expressive of the total amount of carbonic 
acid present in the sea-water examined. 
Unfortunately, divers untoward circumstances conspired 
to prevent my terminating in the winter of 1877 —78 the 
series of experiments l had begun with the object of elu- 
cidating this intricate subject; my time, for instance, came 
to be unexpectedly occupied in other ways, and during the 
greater part of that period I suffered from ill-health. Mv 
observations, therefore, not having progressed so favourably 
as I at first had reason to anticipate, I was again obliged 
to set out on the Expedition, in 1878, without having 
fixed on any reliable method for determining the carbonic 
acid present in sea-water. On my return however to Chris- 
tiania in the autumn of that year, I recommenced the said 
experiments, and succeeded in bringing them to a satisfac- 
tory termination. 
A paper by G. Borchers, which had just appealed, 1 
on the determination af carbonic acid in mineral water, 
drew my attention to the apparatus — of which 1 have 
since made frequent use — devised by Alex. Glassen 2 for 
determining carbonic acid in carbonates. 
Figure 3 represents this apparatus as constructed for 
my experiments. 
A 2 glass tubes, resembling in form the letter U, 
filled with soda-lime; B a vessel for baryta water: C an 
Erlenmeyer flat-bottomed matrass, containing about 0.5 
litre, which by means of a tube terminating at tin* bottom 
is made to communicate with B. a similar tube, issuing im- 
mediately beneath* the caoutschouc stopper, putting it like- 
wise in communication with the cooler D, the inner por- 
tion of which, according to Glassen, should consist of a 
glass tube from 27'" m to 30 mOT in diameter, with tubes, 
measuring respectively 15 mm and l mm in diameter, sealed 
to its upper and lower extreinitfes. The receiver E has 
precisely the same form as that adopted by Jacobsen, and 
is furnished above with a glass tube, F, filled with glass 
balls, as suggested by P. Wagner. 3 
At the point a, where the tube suddenly narrows, is 
introduced a somewhat larger glass ball, to fill up, as near 
as may be, the opening of the lower or slender portion of 
the tube. When the titrated baryta water, which absorbs 
the carbonic acid, is being poured down through F, the 
stopper b has to be taken out, but must he quickly replaced, 
before the whole of the fluid has passed a, in order 
that the glass balls to a height of about 50" m abovt* a 
1 Journ. fur pract. Chem. 125 — 353. 
2 Fresenius Zeitschrift 15 - 288. 
3 Fresenius Zeitschrift 9 — 445, 
1 Journ. fur pract. Chem. 125, p. 353. 
1 Fresenius Zeitschrift 15, p. 288. 
3 Fresenius Zeitschrift 9, p. 445. 
