THE ASH OF PLANTS. 159 



Bark. Wood. Leaf-stems. Leaves. Flou'er-stems. Calyx. 



Potash 12.1 25.7 46.2 27.9 63.6 61.7 



Lime 76.8 42.9 21.7 29.3 9.3 12.3 



Magnesia 1.7 5.0 3.0 2.6 1.3 5.9 



Sulphuric acid trace trace 3.8 9.1 3.5 trace 



Phosphoric acid 6.0 19.2 14.8 22.4 17.1 16.6 



Silica 1.1 2.6 1.0 4.9 0.7 1.7 



Chlorine 2.8 6.1 12.2 5.1 4.7 2.4 



Eipe Fruit. 



4, Similar kinds of plants, and especially the same 

 parts of similar plants, exhibit a close general agreement 

 in the composition of their ashes while plants which are 

 unlike in their botanical characters are also unlike in the 

 proportions of their fixed ingredients. 



The three plants, wheat, rye, and maize, belong, botnnical- 

 ly speaking, to the same natural order, graminece, and the 

 ripe kernels yield ashes almost identical in composition. 

 Barley and the oat are also graminaceous plants, and their 

 seeds should give ashes of similar composition. That such 

 is not the case is chiefly due to the fact, that, unlike the 

 wheat, rye, and maize-kernel, the grains of barley and 

 oats are closely invested with a husk, which forms a part 

 of the kernel as ordinarily seen. This husk yields an ash 

 Avhich is rich in silica, and we can only properly compare 

 barley and oats with wheat and rye, when the former are 

 hulled, or the ash of the hulls is taken out of the account. 

 There are varieties of both oats and barley, whose husks 

 separate from the kernel the so-called naked or skinless 

 oats and naked or skinless barley and the ashes of these 

 grains agree quite nearly in composition with those of wheat, 

 rycj and maize, as may be seen from the following table: 



