37 



den kulsure Kalk i Luret har jeg benyttet et af S. W. 

 Johnson konstrueret Apparat (Zeitschrift fur anal. Chemie, 

 9, S. 90). Dette er fortrinlig skikket til en hnrtig og 

 sikker Bestemmelse af Kulsyren i de let dekomponerbare 

 Karbonater. Johnsens Apparat har den Fordel fremfor 



of carbonate of lime present in oceanic deposit, I made 

 use of an instrument devised by S. W. Johnson (Zeitschrift 

 fur anal. Chemie. 9, S. 90). and admirably adapted for 

 speedy and accurate determination of the carbonic acid in 

 easily decomposable carbonates. Johnsons apparatas has 



Bunsens og de ovrige, at det »ikke nodvendiggjor nogen 

 rdsugning og Udkogning for at fjerne den tilbagehlevne 

 Kulsyre. Apparatet (se ovenstaaende Tegning) med den 

 afveiede Substans fyldes (gjennem a) med tor Kulsyre fra 

 et Udviklingsapparat og veies; derpaa holdes det paaskraa, 

 saa at Saltsyren fra det pæreformige Reservoir rinder over 

 i Kolben. Naar Karbouatet er fuldstændig dekomponeret, 

 ledes Kulsyre atter igjennem og Yeiningen udfores paany. 

 Bestemmelsen kræver neppe en halv Time. 



Med Apparatet fandt jeg i kulsur Baryt ved to Be- 

 stemmelser: 22.27 pCt. og 22.20 pCt.; beregnet: 22.33 pCt. 

 I Bundpr. fra St, 30u fandtes ligesaa 2 AG pCt. og 2.55pCt.C0 2 

 I — „ .. 53 — 12.70 — 12.81 — 



Altsaa en Nøiagtighed som ikke lader noget tilbage at 

 ønske. 



this advantage over Bunsens and other instruments of the 

 kind. that no absorptive, boiling-out process is necessary 

 to get rid of the residuary carbonic acid. The apparatus in 

 question (see Fig. ). containing a given quantity of the 

 substance. is filled (thi'ough a) "with dry carbonic acid, and 

 duly weighed; it is then held obliquely, that the hydro- 

 chloric acid from the pyriform reservoir may Ho w into the 

 flask! So soon as the carbonate of lime is completely 

 decomposed, the carbonic acid is again conducted through 

 the apparatus, and the weighuig carried out as before. 

 Half an hour will amply suffice for the operation. 



With this apparatus, I found in carbonate of baryta. 

 as the result of two determinations, respectively 22.27 per 

 cent and 22. 2o per cent of carbonic acid (by computation 

 22.33 per cent). Again. in the sample of the bottom brought 

 up at Station 300, the proportion thus determined was 

 2.46 per cent and 2.55 per cent: in that from Station 53, 

 12.70 per cent and 12.81 per cent. — a degree of accu- 

 racv that leaves nothing to be desired. 



