29 



ikke ved fortsat Inddampning skulde kunne have erholdt 

 et større Udbytte at' Kulsyre. De at' Dr. Jacobsen og 

 •J. Y. Buchanan udførte Observationer kunde derimod ikke 

 saa ligefrem forkastes, idet der jo kunde tænkes Mulighed 

 tor. at det ved de af dem benyttede Md Innlei' kunde have 

 lykkedes ved den langvarige Sogning at uddrive ogsaa al 

 neutralbunden Kulsyre. i hvilket Fald de af dem opførte 

 Tal i en anden Henseende kumle taa Betydning nemlig 

 som Udtryk for den samlede Sum af den i Sovandet i-nde- 

 holdte Kulsyre. 



Desværre .lagde dere Omstændigheder Hindringer i 

 \"eien for Afslutniugen af mine Forsog over disse Gjen- 

 stande i Vinteren 1877 — 78, dels var min Tid optaget med 

 andre Arbeider, dels lod min Helbred den største Del af 

 Vinteren adskilligt tilbage at ønske, saaat mine Forsøg in- 

 genlunde havde 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- 

 holdte Kulsyre. Da jeg efter endt Togt om Hosten vendte 

 tilbage, gjenoptog jeg imidlertid atter mine Undersøgelser 

 og bragte dem til Afslutning. 



Gjennem en netop da af C. Borchers offentliggjort 

 Afhandling 1 om Bestemmelsen af Kulsyren i naturlige Mi- 

 neralvande blev jeg gjort opmærksom paa det for Bestem- 

 melse af Kulsyren i Carbonater af Alexander Classen angivne 

 Apparat, 2 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 gjennem et ved Bunden udmundende Kor 

 communicerer med B, medens et lige under Kautschuk- 

 proppen udmundende sætter den i Forbindelse med Kjole- 

 leren D. hvis indre Del efter Classen bestaar af et 27 — 

 30""" vidt Glasror. hvortil i øvre og nedre Ende er loddet 

 Bor med respective 15 og 7 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. Ror F. 



Ved a, hvor der lindes en Indsnevring, er anbragt 

 en noget større Glaskugle. som temmelig nøie dækker over 

 det nederste snevre Bør. Idet det til Upsamliug af Kul- 

 syren anvendte, titrerede Barytvand heldes ned gjennem F, 

 fjernes Proppen b, indtil det Meste af Barytvandet har 

 passeret a, men sættes derpaa burtigt i, saaledes at der 

 over de nederste Glaskugler bliver staaende noget Baryt- 

 vand til en Høide af omtrent 50""" over a. Dersom nu 



125 — 353. 



Journ. fur pract. Chem. 

 Fresenius Zeitschrift 15 — 288. 

 Fresenius Zeitschrift — 445, 



series of observations instituted by Dr. Jacobsen and .1. Y. 

 Buchanan cannot however be wholly rejected, since. the 

 protracted boiling cbaracteristic of the luethod tliey adopted 

 may possibly have driven off all the carbouic acid contained 

 in the carbonates. in which case their figures would acquire 

 importance as expressive of the total ainount of carbouic 

 acid present in the sea-water examined. 



Unfortuuately, divers untoward circumstances conspired 

 to prevent my terminating in the winter of 1877 — 78 the 

 series of experiments I 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. My 

 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 terinination. 



A paper by C. Borchers. which had just appeared, 1 

 on the determination of carbonic acid in mineral water, 

 drew my attention to the apparatas — of which I have 

 since made frequent use — devised by Alex. Classen 2 for 

 determining carbonic acid in carbonates. 



Figure 3 represents ■ tliis apparatas as constructed for 

 my experiments. 



A 2 glass tubes, resembling in form the letter U, 

 tilled with soda-lime; B a vessel for baryta water; C an 

 •Erlenmeyer tlat-bottomed matrass, containing about ".5 

 litre, which by means of a tube terminating at the bottom 

 is made to commimicate with B, a similar tube, issuing im- 

 mediately beneath the caoutschouc stopper, putting it like- 

 wise in communication witb the cooler D, the inner por- 

 tion of which, according to Classen, should consist of a 

 glass tube from 27 mm to 30""" in diameter, with tubes, 

 measuring respectively 15 """ and l m - m in diameter, sealed 

 to its upper and lower extremities. 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 tåken out, hut must be quickly replaced. 

 before the whole of the fluid has passed a. in order 

 that the slåss balls to a heigbt of about 50'""' above a 



1 Journ. fur pract. Chem. 125, p. 353. 

 - Fresenius Zertachrift 1"., p. 288. 

 * Fresenius Zeitschrift 9, p. 445. 



