582 MINERAL SPRING AT KIETFONTEIN. 



magnesium in the filtrate was determined as pyrophosphate. 

 Three litres of water gave 0.0109 of a gram of Mg.P.O,, so that 

 100,000 c.c. of water contain 0.0794 of a gram of magnesium. 



Iron. — Determined colorimetrically with ammonium ihio- 

 cyanate. I)ui)licate determinations were made, on 300 and 

 696 c.c. respectively of the ^vater. 'J'he quantities of iron found 

 per 100,000 c.c. of water were respectively 0.0333 and 0.0335 of 

 a gram, giving a mean value of 0.0334 of a gram of ferrous 

 iron. 



Aiiiiiio)iia. — Determined by nesslerising 100 c.c. of water. 

 Two determinations yielded, per 100,000 c.c. of water of 4°, 

 res])ectively 0.0580 and 0.0598 of a gram of NH^^. Hence the 

 mean value per 100,000 c.c. of water of 4° is 0.0623 of a gram 

 of NH^'. The amount of ammonia diminishes raj^idly. and was 

 found to fall to three-fourths of its original value in less than 

 three weeks. The corresjionding increase in the nitrate content 

 has already been referred to. 



Aliiiitliiiuin. — Two determinations were made, each on one 

 litre of water ; in one case a precipitate of A\J )., -f- Fe..O., was 

 obtained, \\eighing 0.0064 of a gram. Therefore 100.000 c.c. of 

 4" contain 0.21380 of a gram of ALO. -f FeoO.,of which 0.4775 

 of a gram is Fe^Os, leaving 0.16605 of a gram of ALO,. In the 

 second determination the result was 0.15600 of a gram of 

 AUG,,. The mean value is 0.08540 of a gram of aluminium per 

 100,000 c.c. of water of 4° C. 



Lifhiuni. — The lithium was determined by ])recipitating the 

 calcium as oxalate, removing the magnesium in the filtrate as 

 hydrate, and i)recipitating the excess of sodium chloride in the 

 solution by means of hydrochloric acid gas. The solution was 

 then evaporated to dryness, and the lithium chloride dissolved 

 out w'ith water-free ether-alcohol. The lithium chloride was 

 converted into the sulphate and weighed as such. 



Three litres of water of 20° gave 0.016:51 of a gram of 

 Li,SO,. 



100,000 c.c. of water of 4° gave 0.54463 of a gram of 

 LioSO,. 



100,000 c.c. of water of 4° contain 0.06927 of a gram of 

 lithium. 



Sodium. — The water was evaporated to dryness, insoluble 

 silica filtered ofif, precipitating iron and aluminium as hydrates, 

 calcium as oxalate, and evaporating the filtrate, containing 

 soditun, magnesium, and lithium, to dryness, with the addition of 

 sul]jhiu-ic acid. Three litres of water of 21° C gave 6.9258 

 grams NagSO^ + MgSO^ -)- Li.SO^, corresponding to 231.3183 

 grams of mixed sulphates, in 100,000 c.c. of 4°, and to 230.3802 

 grams of sodium sulphate. Hence 100,000 c.c. of water of 4° 

 contain 74.5934 grams of sodivim. 



An indirect determination was also made from the amount 

 of chlorine (see under sodium chloride in the calculation of 

 results as undissociated molecules.) 



