158 HOW CROPS GROW. 
silica, potash, and lime, are the principal ingredients. In 
the chaff and husk, silica constitutes three-fourths of the 
ash, while in the grain, phosphoric acid appears as the 
characteristic ingredient, existing there in connection with 
a large amount of potash, (32 °|,,) and considerable mag- 
nesia. Chlorine acquires its maximum, (11.7°|,,) in the 
middle stem, but in the kernel is present in small quantity, 
while sulphuric acid is totally wanting in the lower stem, 
and most abundant in the upper leaves. 
Again, the unequal distribution of the ingredients of 
the ash is exhibited in the leaves of the sugar beet, which 
have been investigated by Bretschneider, (Hoff. Jahresbe- 
richt, 4, 89.) This experimenter divided the leaves of 6 
sugar beets into 5 series or circles, proceeding from the 
outer and older leaves inward. He examined each series 
separately with the following results: 
I. Il. Ti. IV. v. 
POI ri panecanacees 18.7 25.9 32.8 37.4 50.3 
SOd a caie ia ta eaieceheese 15.2 14.4 15.8 15.0 11.1 
Chloride of Sodium... 5.8 6.4 5.8 6.0 6.5 
TAME jee cceneanciwedee 24.2 19.2 18.2 15.8 4% 
Magnesia... 22.3 13.0 8.9 6.2 
Oxide of Iron.. - 0.5 0.6 0.6 0.5 
Phosphoric acid. . 48 5.8 8.4 12.7 
Sulphuric acid. .. 5. 5.6 5.6 5.2 5.9 
Siljca.....seeeeee eee 1.5 0.8 2.7% 21 15 
From these data we perceive that in the ash of the 
leaves of the sugar beet, potash and phosphoric acid reg- 
ularly and rapidly increase in relation to the other ingre- 
dients from without inward, while lime and magnesia as 
rapidly diminish in the same direction. The per cent of 
the other ingredients, viz., soda, chlorine, oxide of iron, 
sulphuric acid, and silica, remains nearly invariable 
throughout. 
Another illustration is furnished by the following anal- 
yses of the ashes of the various parts of the horse-chestnut 
tree, made by Wolff, (Ackerbau, 2. Auf., 134): 
