THE ASH OP PLANTS. 161 



i 



development of the plant, numerous illustrations will be 

 adduced, (p. 214.) 



b. Vigor of development. Arendt, (Die Haferpflanze, 

 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 : 



123 



Silica 27.0 39.9 42.0 



Sulphuric acid 4.8 4.1 5.6 



Phosphoric acid 8.2 8.5 8.8 



Chlorine 6.7 5.8 4.7 



Oxide of Iron 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 per cent more of silica, 

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

 other ingredients is not greatly different. 



Zoeller, (Liebig's Erntihrung der Vegetabilien, 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 partial analysis : 



Shaded clover. Unshaded clover, 



Alkalies 5-1.9 36.2 



Lime 14.2 22.8 



Silica 5.5 12.4 



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. Ghem. Soc., II, p. 20,) analyzed 

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

 on the same soil and under precisely similar circumstances. 

 His results as follows : 



