On the Composition of Oceanic 



must multiply the results in Y by 1-042 to make them com- 

 parable with those in X. 



B. Estimation of Alkalies. 3-7014 grammes were dissolved 

 in hydrochloric acid, and the insoluble part removed as usual. 

 The solution was made up to 250 c.c. ; 100 c.c. of this solution 

 was used for the estimation of the alkalies. In the first place, 

 however, the barium hydrate and ammonium carbonate to be 

 used in the separation were tested for their purity. 5-518 

 grammes of barium hydrate were dissolved in water, and 

 carbonic acid gas passed through the solution to saturation. 

 The whole was then boiled and filtered. The barium carbonate 

 precipitate was dried and roughly weighed. It weighed from 

 2 *95 to 3 grammes, i.e., about 47-6 per cent, of Ba(OH) 2 in the 

 barium hydrate used, the rest being water. The filtrate from 

 the barium carbonate was evaporated nearly to dryness in 

 a platinum basin, a little barium carbonate which settled 

 out was filtered off, and the filtrate evaporated to dryness. The 

 residue was redissolved in water, refiltered, evaporated to 

 dryness again, and weighed. It weighed 0-0017 gramme, 

 i.e., 0-031 per cent, of alkalies as chloride in the baryta hydrate. 

 N.B. This hydrate of baryta had previously been recrystallised. 



The ammonium carbonate was then tested. It was a solution 

 of i part of salt in 5 of water. 5 c.c. of it were evaporated to 

 dryness in a platinum basin, and the residue ignited, and then 

 moistened with hydrochloric acid and ignited again. It 

 weighed 0-0012 gramme, therefore I c.c. of the ammonium 

 carbonate solution leaves 0-00024 gramme of residue. 



To the above-mentioned 100 c.c. solution (containing 1-4805 

 grammes of substance) 4-088 grammes of barium hydrate were 

 added. It dissolved completely, and the whole was allowed to 

 stand over-night. Next morning carbonic acid gas was passed 

 through the turbid solution to saturation, and the solution 

 boiled to get rid of excess of carbonic acid gas ; it was then 

 filtered. The precipitate was dried and transferred to the 

 original flask in which precipitation took place, and the ignited 

 filter ash added. 



The filtrate was evaporated down to a bulk of from 25 to 

 50 c.c., and the barium and calcium present precipitated by 



