

and Littoral Manganese Nodules 195 



ANALYSIS OF THE MUD IN WHICH THE NODULES 

 FROM LOCH FYNE WERE FOUND. 



The mud was air-dried, and had been freed from manganese 

 nodules and shells. The moisture, carbonic acid, available 

 oxygen, manganous oxide, and insoluble residue were deter- 

 mined, with the following results: 



Moisture at 162 C. . . . . . . 5-92 per cent. 



Carbonic acid . . . . . . . . 2-55 



Available oxygen . . . . . . merest trace 



MnO . . . . . . . . . . 0-71 per cent. 



Insoluble residue . . . . . . 74-26 



CuO . . . . . . . . . . distinct traces. 



With regard to the available oxygen, 0-5750 gramme were 

 taken, and, after boiling with strong HC1 as usual, the solution 

 of potassium iodide remained colourless. On adding a little 

 starch solution to it, however, a slight purple tint was produced, 

 which the smallest drop of hyposulphite sufficed to decolourise. 

 There is, therefore, only the smallest possible trace of MnO 2 

 present, and the 0-71 per cent. MnO is really present as MnO. 



ANALYSIS OF PECTEN SHELLS PICKED OUT OF THE 

 LOCH FYNE MUD. 



I'itatire Analysis. These shells were well scrubbed with 

 pure water, so as to free them from all adhering mud, and then 

 Iried. They contained 



Organic matter .. .. A little. 



CO, . . . . . . A large amount. 



SO, . . . . . . Small amount. 



SiO, . . . . Very small amount. 



metals precipitable by H 2 S in HC1 solution. Very 

 1 precipitate with sulphide of ammonium 



CaO . . . . . . Very large amount (no BaO). 



MgO . Trace. 



Qualitative Estimation <\f MnO and P 2 O 8 . 1*5695 grammes 

 itrd with diluU HC1. There was very little organic 



132 



