New York AGRICULTURAL EXPERIMENT STATION. QA5 
while the hays generally contain about 5 to 8 per cent, and the 
seeds of the cereals—grains—usually not more than 2 to 3 per 
cent, although a few contain so much as 4 to 6 per cent. This 
ash is made up of several different elements or constituents, 
each of which the chemist is able to separate out and weigh 
by itself, but not in the same form always in which it existed 
in the plant. There are thirteen of these elements present 
in the ash of our agricultural plants and the names by which 
the chemist knows them are as follows: Oxygen, carbon, sulphur, 
phosphorus, potassium, sodium, calcium, silicon, chlorine, fluorine, 
iron, Magnesium, manganese. 
Besides these there are found in a few plants other elements, 
such as aluminum in wheat and iodine in some of our sea plants. 
The amount of fluorine in plants is very small, seldom more than 
a trace, and of iron there is rarely found more than one per cent. 
Yet this small amount of iron is an absolute essential for. the 
_development of the normal plants. If there is a lack of iron the 
plant becomes pale, and the leaves are white and growth stops ; 
but let iron be supplied to such a plant and the leaves again 
become of a deep green, healthy color. The plant secures its 
oxygen and carbon from the air, but the other elements all come 
from the soil, which is the only source of supply. The chemist in 
separating these elements of the ash, determines them in some 
form of their compounds and in the analysis he gives names more 
familiar to the farmer, as follows, using also certain letters and 
figures as abbreviations or symbols for the real form : 
Phosphoric acid (anhydride P,O,). | 
Sulphuric acid (or anhydride SQ,). 
Carbonic acid (or anhydride CO,). 
Potash, K,O. 
Soda, Na,O). 
Lime, CaO (calcium). 
Silica, Si0,, 
Ferric oxide, Fe,O; (iron). 
Magnesia, MgO. 
By stating the elemental compounds in the above form the 
chemist does not mean to say that they always are found in the 
plants in just this form, for in the plant the elements are com- 
bined in several forms, and these combinations sometimes change 
as the plants approach maturity. Thus phosphorus, nor 
