222 TlIF, MKUICINAL SPRINGS OF SOUTH AFRICA. 



II. 500 c.c. of water of 1 1 .6" j^^ave 0.0223 gram of SiO., -p 



BaSO,,. 



III. 2 litres of 12" gave 0.0753 gram of SiO. -|- BaSOj. 

 100,000 c.c. of water of 4° therefore contain 3.9273 



grams of SiOg and 0.2000 gram of BaSO^, correspond- 

 ing to 0.1 177 gram of barium. 



Chlorine. 



I. 25 c.c. of water of 10° require 29. i c.c. AgNO... of which 



ICC. corresponds to i mg CI. 



N 



II. 25 c.c. of 12° require 40.95 c.c. — AgNO:^. 



100,000 c.c. of water of 4° therefore contain 116.33 

 grams of chlorine. 



Sulphuric Acid {50.^). — Two litres of water of {2.()^° give 

 0.0145 gram BaS04, corresponding to 0.2984 gram SO^ per 

 100,000 c.c. to which must be added 0.0823 gram from the BaSO.j 

 precipitated with the SiOo, giving a total of 0.3807 gram of 

 SO4 per 100,000 c.c. of water of 4°. 



AlkaJinit\. 



N 

 50 c.c. of water of 14.3° are neutralised In' 1.15 c.c. — r 



H^SO^ (four estimations). 



100,000 c.c. of 4° therefore contain 2,8204 gi'anis HCO... 



Determination of the Cations. — Calcium. 



I. 500 c.c. of water give 0.0605 .^''am Ca( ). 



II. 1,000 c.c. of water give 0.1179 gram CaO. 



100,000 c.c. of water therefore contain 11.945 grams 

 CaO, corresponding to 8.5375 grams of calcium. 



Iron. 



Determined colorimetrically with thiocyanate solution (two 

 determinations). 



50 c.c. of water contain the same amount olf iron as 0.2 c.c. 



of a standard ferric chloride solution, of which i c.c. 



corresponds to o.i mg. Fe. 

 100,000 c.c. of water therefore contain 0.04 gram 1 if iron. 



Aluuiiu'uui. 



2 litres oif 12° give 0.0099 Fe^Og -(- ALO... 



Subtracting the iron leaves 0.338 gram Al,( ),, per 100,000 

 c.c. of 12°, corresponding to 0.1793 gram oi alumin- 

 ium in 100. oco c.c. of water of 4°. 



Auunouia. 



298 c.c. oi water correspond to i c.c. NH^Cl solution con- 

 taining 0.1 mg NH.. per c.c. (Nesslerised ; four esti- 

 mations). 



