EEPOET ON THE COMPOSITION OF OCEAN-WATEE. 
109 
the solution was determined analytically by Torn0e’s method. Assuming the soda and 
the carbonic acid to be associated in the proportion of Na 2 0 : 2C0 2 , the resulting alkalinity 
corresponded to 1097 mgrms. of carbonic acid per litre of liquid, instead of 110 ’0 mgrms., 
as demanded by the synthesis. Found, after n shakings with air, for 
n= 2. 4. 6. 8. 
Carbonic acid, mgrms. p. litre=107‘6 107'8 108 - 0 107 - 8 
This shows that a solution of bicarbonate of soda in pure water is hardly, if at all, 
affected by contact with air at ordinary temperatures. 
II. Pure Solution of Bicarbonate of Magnesia. 
Commercial magnesia alba was washed with water to remove adhering alkali-salts, 
then made into a milk with water, and treated with carbonic acid gas until the most of 
the precipitate was dissolved. Solution filtered and titrated with aurine. 100 c.c. found 
to be equivalent to 9 8 '8 x — ~ x [HC1] milligrammes. 
Zt fi 
200 c.c. of this liquor were diluted with Loch Katrine water # to 2000 c.c. Neglecting 
the alkalinity of the Loch Katrine water, and assuming the existence in the solution of 
the ratio MgO : 2CO a , the solution should contain 197 '6 mgrms. of carbonic acid per litre. 
A direct determination of the alkalinity of the finished solution gave 211 A mgrms. This 
latter number was adopted. Successive measured volumes of this solution were shaken 
n times with 10 volumes of air, and the carbonic acid in the resulting liquor deter- 
mined— 
v = 2. 4. 6. 8. 
x = Carbonic acid, mgrms. p. litre = 207-0 202-3 195-8 193'S 
211-4- x = 4-4 9-1 15-6 17-6 
That is to say, by eight shakings with air about -}■ th of the loose carbonic acid of the 
bicarbonate of magnesia was eliminated 
III. Experiments with Artificial Sea-Water. 
56 grms. of pure chloride of sodium and 27 '5 grms. of pure sulphate of magnesia 
(MgS0 4 , 7H 2 0) were dissolved in distilled water and diluted to 1900 c.c. To this 100 c.c. 
of the bicarbonate of magnesia solution (the same as used for the above experiments) were 
added to produce 2 litres of a quasi sea-water of exaggerated alkalinity. As the salts had 
not been specially purified, their alkalinity was determined analytically. 7 grms. of the 
chloride of sodium plus 3 ’44 grms. of the sulphate of magnesia were found equivalent to 
0-58 mgrms. Hence the alkalinity of the “ sea- water,” by calculation, was thus 
composed per litre — 
* We bad run short of distilled water. 
