THE ASH OF PLAINS. 161 



development of the plant, numerous illustrations will be 

 adduced, (p. 214.^ 



h. Vigor of development. Arendt, {Die ITaferpJlanse, 

 p. 18,) selected from an oat-field a number of plants in 

 blossom, and divided them into three parcels — 1, composed 

 of very vigorous plants ; 2, of medium ; and, 3, of very 

 weak plants. He analyzed the ashes of each parcel, with 

 results as below : 



12 3 



Silica 3T.0 39.9 42.0 



Sulphuric acid 4.8 4.1 5.6 



Phosphoric acid 8.3 8.5 8.8 



Chlorine 6.7 5.8 4.7 



Oxideoflron 0.4 0.5 1.0 



Lime 6.1 5.4 5.1 



Magnesia, Potash & Soda. 45.3 34.3 30.4 



Here we notice that the ash of the weak plants contains 

 15 per cent less of alkalies, and 15 peT cent more of silica, 

 than that of the vigorous ones, while the proportion of the 

 other ingredients is not greatly different. 



Zoeller, {Liehig's JErnahrung der YegetdbiUen, p. 340,) 

 examined the ash of two specimens of clover which grew 

 on the same soil and under similar circumstances, save 

 that one, from being shaded by a tree, was less fully devel- 

 oped than the other. 



Six weeks after the sowing of the seed, the clover was 



cut, and gave the following results on j^artial analysis : 



Skadeti dover. Unshaded clover. 



AlkaUes 54.9 36.3 



Lime 14.3 22.8 



Silica 5.5 12.4 1 



c. The variety of the plant or the relative development 

 of its parts must obviously influence the composition of 

 the ash taken as a whole, since the parts themselves are 

 unlike in composition. 



Herapath, {Qu. Jour. Chem. Soc.,H,p.2Q,) analyzed 

 the ashes of the tubers of five varieties of potatoes, raised 

 on the same soil and under precisely similar circumstances. 

 His results are as follows : 



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