VARIOUS METHODS OF ANALYSING ASHES. 
369 
phate of lime, as frequently some is found in ashes which con- 
tain much phosphate of lime. If this precipitate be again dis- 
solved in dilute muriatic acid, diluted with water, and heated to 
boiling with the addition of acetate of soda, it is obtained free from 
every trace of phosphate of lime. After the alumina and peroxide 
of iron have been precipitated by acetate of soda from the acid 
extract of the ash in the state of phosphate, the separated liquid 
is mixed with a solution of perchloride of iron (the amount of iron 
which is known and equal in weight to about the tenth or twenti- 
eth part of the entire weight of the ash), in order to determine 
the phosphoric acid still contained in it ; the liquid itself is diluted 
with a considerble amount of water, heated to boiling in a flask 
with the addition of 0.5 grm. chlorate of potash, somewhat neu- 
tralized with carbonate of soda, and the whole of the iron added 
to the liquid thrown down as basic phosphate by a further addition 
of acetate of soda. The precipitate is collected on a filter, washed, 
dried, and ignited in a platinum dish after having been moistened 
with a few drops of nitric acid, and in this way a basic phos- 
phate of iron obtained perfectly free from protoxide. The liquid 
filtered from the basic phosphate of iron is heated to boiling in a 
flask with carbonate of soda, in order to precipitate lime, magnesia 
and protoxide cf manganese as carbonates. The filtered liquid is 
mixed with some phosphate of soda and ammonia, and the crystal- 
line precipitate of ammonia-phosphate of magnesia obtained after 
twelve to twenty-four hours, added to that portion to be mentioned 
hereafter. The mixed precipitate of earthy carbonates is, after 
drying, heated to a strong red in a porcelain crucible, then dissolv- 
ed in cold dilute nitric acid. If any manganese be present, it is 
left as Mn 3 4 , The separated liquid is mixed with oxalate of 
potash, the oxalate of lime calcined after drying, and calculated 
from the amount of carbonate. After separating the oxalate of 
lime, the liquid is mixed with ammonia-phosphate of soda free 
from magnesia. The crystalline precipitate obtained in the 
course of twelve hours' standing is mixed with that previously 
obtained, calcined, and the weight of magnesia calculated from it. 
As the salts of potash cannot be always completely removed 
from the ashes by water, the second half of the acid solution is 
separated from all the earths by carbonate and caustic ammonia, 
the liquid evaporated to dryness, heated to redness to remove the 
