490 



DR JOHN MURRAY AND MR ROBERT IRVINE ON THE 



The discordance between the chlorine found and the chlorine calculated from the 

 total bases as sulphates is thus shown to be an effect due to the precipitation of carbonate 

 of lime (CaC0 3 ) in the mud. The chlorine in the mud-water as found by analysis is the 

 same in amount as that present in normal sea-water of density 1026, and we may suppose 

 that this was the kind of sea-water mixed up with the mud before any chemical change 

 took place, but now it has been so changed as to be unrecognisable either by its density 

 or the amount of its total bases, while the halogen values are the same if determined 

 directly but not if calculated from the density or total bases. 



The apparent diminution of chlorine, in the 1st portions of the waters, is caused by 

 the oxidation of the sulphide of iron increasing to a large extent above the normal 

 the amount of sulphates and carbonic acid in these portions,* which has the effect of 

 increasing its density by an increase of total salts relatively to the chlorine, but apparently 

 correspondingly diminishing the chlorine. 



If we take the mean of 3rd, 4th, and 5th portions in Tables II. and IV., the change 

 that has taken place in the water associated with the mud, compared with normal sea- 

 water, will be observed, and indicates in what direction to look for changes produced in 

 other less typical waters. The following table shows the salts in normal ocean- water 

 and the salts found in the mud- waters : — 



TABLE C. — Showing the Average Composition of Normal Sea- Water Salts and Mud-Water Salts, 



with their relation to Halogen. 











Per 100 of Total Salts. 



Per 100 of Halogen (calculated 

 as Chlorine). 





Average Sea- 

 Water, f 



Mud-Water. 



Average Sea- 

 Water, f 



Mud-Water. 



Chlorine, CI, 

 Bromine, Br, 

 Sulphuric Acid, S0 3 , 

 Carbonic Acid, C0 2 , 

 Lime, CaO, 

 Magnesia, MgO, . 

 Potash, K 2 0, 

 Soda, Na 2 0, 

 Ammonium Oxide, (N 



a 4 ) 2 o 







55-292 

 0-188 

 6-410 

 0-152 

 1-676 

 6-209 

 1-332 



41-234 



56-239 

 0-191 

 3-424 

 1-656 

 1-504 

 6-315 

 1-355 



41-941 

 0-081 



99-848 

 0-340 



11-576 

 0-274 

 3-026 



11-212 

 2-405 



74-462 



99-848 

 0-340 

 6-07!) 

 2-911 

 2-670 



11-212 

 2-405 



74-462 

 0144 



Less Basic Oxygen, ( - 0) . 



-12-493 



-12-706 



- 22-559 



- 22-559 











100000 



100-000 



180-584 



177-542 



* This reaction may be stated thus :— The sulphide of iron in the mud is oxidised by the atmosphere into sulphate, 

 which reacts on carbonate of lime in the mud or in solution, forming sulphate of lime and momentarily carbonate of iron, 

 changing to oxide of iron, liberates carbonic acid, which, along with the sulphate of lime, remains in solution ami increases 

 the density of these 1st pm twits. 



•t See Dittmar, op. cit., part i. pp. 137-138 and 203. 



