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7.—EsTIMATION oF THE CarBonic AciD Gas IN SOLUT™ON. 
100ce. of the sea water was mixed with a slight ex” ss of 
barium chloride solution and warmed till the precipitate 
had settled. This was then filtered and washed, and 
repeatedly treated with known amounts of standard 
hydrochloric acid. As the precipitate would consist of 
barium carbonate and barium sulphate, it was hoped that 
the hydrochloric acid would dissolve the former. The acid 
solution was then boiled to drive off the earbonic acid, and the 
excess of acid estimated by titration with standard alkali, 
using aurine as indicator. The alkalinity, determined by 
methodsalready described, was subtracted from the value thus 
obtained, when the difference was supposed to represent 
the carbonic acid directly dissolved in the water. 
This ought to be an accurate method, but probably it is 
not, for so many processes have to be gone through that 
the accumulated iron due to each probably amounts to 
some considerable sum. For this reason it was only 
attempted in one or two cases, and as the results seem open 
to suspicion, they are not given. 
8.—EstTIMATION OF LIME. 
Owing to lack of time this was only done in a very few 
eases. 100cc. of the sea water were mixed with ammonium 
chloride solution and an excess of ammonium oxalate, and 
the mixture was warmed till the precipitate settled. It was 
then filtered off, washed, dissolved in dilute sulphuric acid, 
and the oxale acid estimated by titration in the heat with 
standard potassium permanganate. 
The permanganate solution was standardised against 
weighed amounts of ferrous-ammonium sulphate. It was 
then used at once. 
Cc 
