and Littoral Manganese Nodules 191 



the addition of 5-5 c.c. of ammonium carbonate. This precipi- 

 tate was dried and added, along with its filter ash, to the flask 

 in which were the other bases and excess of barium carbonate. 

 The reason for doing this was, that on evaporation of the 

 filtrate from the bases, a further small quantity of a dark- 

 brown precipitate (MnO 2 most likely) came down. 



The filtrate from the ammonium carbonate precipitate was 

 evaporated to dryness in a platinum basin, the ammonium 

 salts driven off, and redissolved in water. A good deal of grey 

 powder, probably barium carbonate, remained undissolved. 

 This was added to the precipitate of bases mentioned above. 

 The filtrate was evaporated to dryness and ignited. It weighed 

 0-0279 gramme. This, then, is the weight of alkalies as 

 chlorides. \Yhen dissolved in water it left a mere trace of 

 insoluble matter, coloured with carbon. This was filtered off, 

 ignited, and weighed. It weighed 0-0004 gramme. 



Thus, to find the weight of alkalies as chlorides in the 

 1-4805 grammes of nodules used, we have to subtract from 

 0-0279 gramme 0-00132 gramme (residue left by 5-5 c.c. 

 ammonium carbonate solution) + 0-00127 (which is the residue 

 in 4-088 grammes of barium hydrate) + 0-0004 (insoluble 

 matter). This leaves 0-02491 gramme (or 1-68 per cent.) of 

 alkalies weighed as chlorides. 



The potassium in the above alkaline salts was estimated by 

 means of platinic chloride. 0-01356 gramme of the double 

 chloride of potassium and platinum (2KC1 . PtCl 4 ) were found- 

 that is, 0-01356 gramme of potassium < hloride in 1-4805 

 inu-s of nodules, or 0-91 per cent, of KC1. This is equiva- 

 li-nt to 0-45 per cent, of K 2 O, leaving 0-41 per cent, of NajO. 



The error due to the ratio of potash to soda in the nodulrs 

 being different from that in the reagents can be but trifling. 



C. A nalysis of the Precipitate of Bases obtained in separating 

 the Alkalies. Dissolved this piv< ipitate in hydrochloric acid, 

 ami ma-It- up tin- ><>lution to 250-85 C.C. 



Billion of Manganese. Took 100 c.< ni the above 

 solution (0-5902 gramme nodules). Evaporated to dryness to 

 get rid of excess of acid, took up tht \\ith \\.itn. ,m<l. 



as ii>u;il. added barium carbonate to precipitate iron and 



