150 Generation of Sulphur in 



The following was the method used in the case of the Loch 

 Duich mud from 49 fathoms. Two portions of the damp 

 unaltered mud were weighed out; one portion, 6-724 grins., 

 was dried at 100 C., and the other, 7-881 grms., was treated 

 with deep red Fe 2 Cl in a 100 c.c. flask, which was then filled 

 up to the mark with water. 50 c.c. of this solution, containing 

 3-94 grms. damp mud, were acidified with sulphuric acid 



and titrated with permanganate ( grms. per litre J , 



using 1-9 c.c. To the remaining 50 c.c. with sediment (the 

 volume of which may here be neglected) were added 4 c.c. 

 of strong hydrochloric acid (12-5 HC1 grms. per litre), filled 

 up to the mark, and allowed to settle. 50 c.c. of this solution, 

 containing 1-97 grms. damp mud, were further acidified with 

 sulphuric acid and titrated with the same permanganate, 

 of which 1-7 c.c. were used. A litre of the above permanganate 

 oxidises 5-6 grms. iron from the ferrous to the ferric state. In 

 the first operation, 50 c.c. solution used 1-9 c.c. permanganate, 

 therefore the whole amount of mud, 7-881 grms., when treated 

 with ferric chloride, would require 3-8 c.c. = 0-0213 grm. iron. 



After treatment with hydrochloric acid a quantity of 

 solution equivalent to 1-97 grms. wet mud required 1-7 c.c. 

 permanganate, so that 7-881 grms. mud would require 6-8 c.c. 

 when treated with both HC1 and Fe 2 Cl 6 , which represents 

 0-0381 grm. iron. Therefore, total iron found by 



Permanganate in HC1 + Fe 2 Q 6 solution . . 0-0381 grm. 

 Deduct Iron found in Fe 2 Cl 6 solution . . 0-0213 ,, 



Leaves Iron present as Ferrous Salt extracted ) 



, TT J 1-1 A "J >0'0l68 



by Hydrochloric Acid j 



Of the 0-213 grm. iron found in the first solution we have 

 seen that only one-third is to be reckoned as belonging to the 

 mud, and to be taken as forming FeS, so that in 7-881 grms. 

 wet mud we have 0-0071 grm. iron present as sulphide, equal 

 to 0-0112 grm. FeS, and 0-0168 grm. iron present as ferrous 

 oxide extracted by hydrochloric acid, equal to 0-0216 grm. FeO. 



The 6-724 grms. wet mud weighed when dried at 100 C., 

 during which it was oxidised as well as dried, 2-011 grms., 



