II 
158 
Analysis of Alkaline Salts and Insoluble Substances in the 
Ashes of Wheat Straw. —By M. Berthier. 
1" Sulph. Acid 
.020 
r Phosphoric Acid . 
.012 
uO L Li. uJLG 
Ilydroclil. Acid 
.130 
Silica. 
.750 
Compounds 
( Silica 
.350 
Compounds - 
Lime. 
.058 
Potash I 
Insoluble 
Oxide of Iron . . 
.025 
Soda )- 
.500 
[_ Carbon and Loss . 
.155 
Water J 
1,000 
1.000 
Magnesia and Oxide of Manganese are found in fhe ashes of oak hark. The 
following Analysis is also given of "Wheat Straw by M. Berthier, as quoted by 
Boussingault: 
Sulph. Potash. 
.004 
Chloride Potasium . . . 
.032 
It will be seen that Potasium enters 
Silicate of Potash . . . 
.130 
in three forms, and Lime in two; while 
Silica. 
.715 
Silica composes nearly three-fourths of 
Carbonate Lime .... 
.096 
the whole. 
Phosphate of Lime . . . 
.023 
1.000 
These substances are not taken from the air but exist in the soil, for 
this must be considered as the source of the saline and earthy matter 
found in plants. Plants indigenous to a sandy soil are richer in silica 
than those found in clay soils ; but opinions are divided, whether the soil 
or manures have the greater influence, but it is sufficient for our purpose 
to know that both exert a powerful influence on the development of vege¬ 
tation, and the question proposed is simply this : Whether mineral or 
vegetable manures are most efficacious ? both are necessary. Many of 
the substances taken up by plants are soluble in water, and thus easily 
enter the circulatory organs ; but the mystery still remains unsolved 
how plants can assimilate insoluble substances—for example: silica, which, 
is insoluble in water, forms nearly three-fourths of the solid matter of wheat 
straw, and in the common scouring rush (Equisetum Iiyemale) the silex 
is perceptible to the touch. But the fact of the assimilation is known, 
and however curious it might be to enquire into the modus operandi, it 
would not affect materially the question before us. The plant does select 
the most congenial substances and in healthy state refuses all others. 
