THE ASH OF PLANTS. 143 



and under the same conditions, Herapath, (Qu. Jour. 

 Chem. Soc., II, p. 20,) found the percentages of ash in 

 dry matter of the tuber as follows : 



Variety of potato. White Prince's Axbridge Magpie. Forty- 



Apple. Beauty. Kidney. fold. 



Ash per cent .4.8 3.6 4.3 3.4 3.9 



7. It has been observed further that different individuals 

 of the same variety of plant, growing side by side, on the 

 snme soil, (in the same field at least,) contain different pro- 

 portions of ash-ingredients, according as they are, on the 

 one hand, healthy, vigorous plants, or, on the other, weak 

 and stunted. Pierre, (Jahresbericht uber Agriculturchemie, 

 III, p. 125,) found in entire colza plants of various degrees 

 of vigor the following percentages of ash in dry matter : 



In extremely feeble plants, 1856 8.0 per cent of ash 



In very feeble plants, 1857 9.0 " 



In feeble plants, 1857 11.4 " 



In strong plants, 1857 11.0 " 



In extremely strong plants, 1857 14.3 " 



Pierre attributes the larger per cent of ash in the strong 

 plants to the relatively greater quantity of leaves devel- 

 oped on them. 



Similar results were obtained by Arendt in case of oats. 

 Wunder, ( Versuchs~St,, IV, p. 115,) found that the leaves 

 of small turnip plants yielded somewhat more ash, per 

 cent, than large plants. The former gave 19.7, the latter 

 16.8 per cent. 



8, The reader is prepared from several of the foregoing 

 statements to understand partially the cause of the varia- 

 tions in the proportion of ash in different specimens of the 

 same kind of plant. 



The fact that different parts of the plant are unlike in 

 their composition, the upper and outer portions being, in 

 general, the richer in ash-ingredients, may explain in some 

 degree why different observers have obtained different 

 analytical results. 



It is well known that a variety of circumstances in- 



