i i 
Gilattie 20 te? 2 
ANALYSIS OF MINERAL WATERS. 269 
hhad been complete. To establish its accuracy with more cer- 
tainty, the following experiments were also made. 
Twenty grains of muriate of soda (pure rock-salt), which had 
been exposed to a red heat, and ten grains of crystallised mu- 
riate of magnesia, were dissolved in an ounce of water, at the 
temperature of 100°. The phosphate of soda and carbonate 
of ammonia were then employed .to precipitate the magnesia in 
the mode proposed by Dr Worzasron, that is, a solution of 
the ammoniacal carbonate was first added, and afterwards a so- 
lution of phosphate of soda, as long as any precipitation was 
produced, taking care to preserve in the liquor a slight excess 
of the ammonia. ‘The precipitate being washed and dried, af- 
forded, after exposure tod a red heat for an hour, 5.4 grains of 
phosphate of magnesia, equivalent to 2.15 of magnesia. The 
clear liquor being evaporated, muriate of soda was obtained, 
which, after exposure to a red heat, weighed 25.77 grains. 
Phosphate of magnesia being composed of 39.7 of magnesia, 
with 60.3 of phosphoric acid, 5.4 grains of it are equivalent to 
6.4 grains of muriate of soda, and this deducted from the quan- 
tity obtained 25.7, leaves 19.3 as the quantity originally dissol- 
ved. , 
- A solution perfectly the same was prepared, and a solution 
‘of carbonate of ammonia was added to it as before. A strong 
solution of phosphoric acid was then dropped in, as long as 
any precipitation was produced, observing the precaution of 
_ having always an excess of ammoniacal carbonate in the li- 
quor. ‘The precipitate being washed and dried, afforded, after 
exposure to a red heat, 5.5 grains of phosphate of magnesia 
equivalent to 2.19 of magnesia. The clear liquor being evapo- 
rated, and the dry matter being exposed to a heat gradually 
raised to redness, weighed, when cold, exactly 20 grains. 
ba ever In 
