56 0. B. B0GGILD. BOTTOM DEPOSITS. APPENDIX I. [norw. pol. exp. 



of the iron reduced to the Ferrous state and again determined by the same 

 method. These titrations furnished the data for calculating both the Ferrous 

 and the Ferric Oxides. To the solution obtained after these operations 

 Ammonium Chloride, Ammonia and a slight excess of Ammonium sulphide 

 were added. The precipitated Fe., Mn. etc., was then filterred off, the filtrate 

 warmed and an excess of solid Ammonium Oxalate added to precipitate the 

 Calcium. The Calcium Oxalate was filtered off, dissolved in HC1 and repre- 

 cipitated with Ammonia, to remove traces of Magnesium possibly carried down 

 with it. Finally it was transferred to a Berlin porcelain crucible, carefully 

 heated and weighed as Carbonate; it was then treated with a drop of 

 Ammonium Carbonate solution, gently warmed and reweighed, the operation 

 being repeated until a constant weight was obtained. In this way it was 

 made quite certain that the Calcium was quantitatively in the form of 

 Carbonate. 



It was feared that the determination of the Iron might not be quite exact 

 by this method, owing to partial oxidation of the HC1, even though rather 

 dilute, by the Permanganate 1 . To make quite sure of this, a similar quantity 

 of the original sample was treated in the same way as before but with 30 % 

 Sulphuric Acid, instead of Hydrochloric Acid, and the estimation of the Iron 

 repeated as a control. It will be seen that the agreement of the two methods 

 is satisfactory; though a lack of agreement might possibly not be regarded as 

 unsatisfactory, inasmuch as there is no reason to suppose that the two 

 methods would furnish the same results in the case of every clay. 



The Carbonic Acid was determined gasometrically; the apparatus 

 used, which has been specially designed for determining the gases dissolved 

 in sea water 2 , allowed the clay to be introduced, boiled with acid and the 

 volume of the Carbonic acid evolved, to be estimated with an accuracy of a 

 few hundredths of a cc. — an order of accuracy higher than here required. 



1 This is the method as used by Tornoe and subsequently by almost all who have 

 carried out thiskind of analysis. It appears to be rather reliable as the analyses 

 here recorded also appear to show, but according to my experience it is better to do 

 the titration with Permanganate after adding a solution of Manganese Sulphate and 

 Phosphoric acid to the Iron solution. The end point is then much more permanent 

 as well as sharper. (See Classen, AusgewShlte Methoden der Analytischen Chemie. 

 Braunschweig 1901. Vol. 1. p. 455). 



1 See Charles J. J. Fox, On the Determination of the Atmospheric Gases dissolved in 

 sea-water. Publications de Circonstance No. 21 du Conseil permanent international 

 pour l'exploration de la mer, Copenhague 1905. 



