THE VOLATILE PART OF PLANTS. 45 
of the solution of phosphoric acid obtained in Exp. 18. To one, add 
some lime-water (see note p. 36) until a white cloud or precipitate is per- 
ceived. This isa phosph_te of lime. Into the other portion, drop solu- 
tionofalum. A translucent cloud of phosphate of aluminais immediately 
produced. 
In soils and rocks, phosphorus exists in the state of 
such phosphates of lime, alumina, and iron. 
In the organic world tue chemist has 28 yet detected 
phosphorus in other states of combination in but a few 
instances. In the brain and nerves, and in the yolk of 
eggs, an ot containing phosphorus has been known for 
some years, and recently similar phosphorized oils have 
been found in the pea, in maize, and other grains. 
We have thus briefly noticed the more important char- 
acters of those six bodies which constitute that part of 
plants, and of animals also, which is volatile or destruct- 
ible at high temperatures, viz.: carbon, hydrogen, oxygen, 
nitrogen, sulphur, and phosphorus. 
Out of these substances chiefly, which are often termed 
the organic elements of vegetation, are compounded all 
the numberless products of life to be met with, either in 
the vegetable or animal world. 
ULTIMATE COMPOSITION OF VEGETABLE MATTER. 
To convey an idea of the relative proportions in which 
these six elements exist in plants, a statement of the 
ultimate or elementary percentage composition of several 
kinds of vegetable matter is here subjoined. 
Grainof Strawof Tubersof Grain of Hay of Red 
Wheat. Wheat. Potato. Peas. Clover. 
BEPODON Ge scale sceeesae 46.1 48.4 44.0 46.5 47.4 
HAVEN scccccscescccs 88 5.3 5.8 6.2 5.0 
MERCI salt sive. sive es'e.0 43.4 38.9 44.7 40.0 37.8 
INUEEGS CR cuisine ss 220s 000s 2.38 0.4 1.5 4.2 2.1 
Ee ing sul 
ie see 
PPE deccccvccessss 0,12 0.14 0.08 0.21 0.18 
Phosphorus............. 0.30 0.80 0.34 0.34 0.20 
