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 is a phosphate of lime. Into the other portion, drop solu- 
tion of alum. Atranslucent cloud of phosphate of alumina is immediately 
produced. 
In soils and rocks, phosphorus exists in the state of 
such phosphates of lime, alumina, and iron. 
In the organic world the chemist has as 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 oil 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 Tudersaf Grain of Hay of Red 
Wheat. Wheat. Potato. Peas. Clover. 
Carbon ....ecceeveveeee - 46.1 48.4 44.0 46.5 47.4 
Hydrogen............... 5.8 5.3 5.8 6.2 5.0 
Oxygen......ce00e aeeeee 43,4 38.9 44.7 40.0 37.8 
Nitrogen.........eeee00 23 0.4 1.5 4,2 2.1 
Ash, including sulphur 
1 a puBpREte had 7.0 4.0 3.1 a 
Sulphur... O12 O14 008 021 0.18 
Phosphorus......ssse00+ 0,80 0.80 0.34 0.34 0.20 
