106 R. A. Daly — Limeless Ocean of Pre- Camhr 'tan Time. 



urine meanwhile decomposing and furnishing the alkaline car- 

 bonate. 



Table VII. 



Water and organic matter containing ammonia (7 - 3S p. c.) 31*81 



Carbonate of lime 4-85 



Phosphate of magnesia and ammonia 51-10 



Phosphate of lime - - 12-24 



100-00 



Table Till shows the composition of the precipitate thrown 

 out of the mixture (after filtration from the precipitate which 

 was thrown out in seven days), standing other ten days. 



Table VIII. 



Water and organic matter .". _ 20'25 



Carbonate of lime . 75-35 



Carbonate of magnesia 1-02 



Phosphate of magnesia 3-38 



100-00 



These tables* prove that the magnesium carbonate came 

 down only after much, perhaps nearly all, of the calcium was 

 precipitated as carbonate. It should also be observed that a 

 considerable amount of the precipitating alkali, ammonia, was 

 removed from the mixture in the first precipitate. 



Murray and Irvine have also investigated the composition 

 of the water filtered out of the mud dredged from the bottom 

 in Granton Harbor and also near the Forth Bridge.f The 

 following table gives the resulting total analysis of the salts 

 of the average mud-water and also bears a column indicating 

 the analysis of average sea-water : — 



Average 

 Sea-water Mud-water 



Sodium chloride 77-758 79-019 



Magnesium chloride 10-878 11-222 



Magnesium bromide 0-217 0-220 



Magnesium sulphate 4-737 3-232 



Potassium sulphate 2*365 2-506 



Ammonium sulphate 0*206 



Magnesium carbonate -. - 909 



Calcium carbonate 0*345 2-686 



Calcium sulphate 3-600 



lOO'OOO 100-000 



* Murray and Irvine, op. cit. ,.p. 104. 



\ Transactions, Koyal Society of Edinburgh, vol. xxxvii, p. 490, 1895. 



