MINERAL SUBSTANCES IN ORGANS OP PLANTS. 265 
caustic ammonia freed from carbonic acid, precipitated from 
their acid solution. The liquid was then filtered, and the 
lime determined by oxalate of ammonia, and after this had 
been separated, the magnesia was precipitated by phosphate 
of soda. 
I selected for the first experiment the ashes of pyrus spec- 
I tabilis, and analysed the ashes of the trunk, the leaves and 
fruits, each by themselves. 
1. Trunk. — The trunk, after having been cut into small 
pieces, burns easily, and on being calcined over a spirit 
lamp finally yields white ashes amounting scarcely to 0.1 
per cent, carbon. Since they contained carbonic earths in 
considerable quantities, it was necessary to moisten them 
after calcination with carbonate of ammonia, to restore the 
carbonic acid which was driven off by the heat. Water 
dissolves but little of the ashes ; in the watery solution, 
which is of a feeble alkaline reaction, are no phosphoric al- 
kalies, but merely traces of carbonates contained. The 
constituent parts soluble in water amount to 4 per cent. 
These ashes consist chiefly of carbonate of lime, amounting 
to 82 per cent. Magnesia enters only at an admixture of a 
trifle per cent. The ashes contain 8 per cent, of insoluble 
phosphates, viz., phosphates of lime and phosphates of 
magnesia. 
2. Leaves. — The ashes are perfectly white, and little so- 
luble in water, which liquid extracts from them 7 per cent, 
of alkaline carbonates, with traces of sulphate of potassa, 
chloride of sodium and phosphate of potassa. These ashes, 
like those of the trunk, chiefly consist of carbonate of lime ; 
in them, however, amounting to less by 10 per cent. The 
phosphate of lime and magnesia amount in these ashes to 
10 per cent. The quantity of magnesia is nearly two-fold; 
it was 4.9 per cent., and is now 9.76 per cent. 
3. Fruits. — Totally discrepant from both the ashes of the 
trunk and leaves are those of the fruit. The soluble parts 
of the other ashes amounted to 4 — 7 per cent. ; those con- 
vol. x. — no. iv. 24 
