142 HOW CKOPS GROW. 



lower leaves exhibited an increase of fixed matters after 

 the first period, while in the upper leaves the ash dimin- 

 ished toward the third period, and thereafter increased. In 

 the ears, and in the entire plant, the ash decreased quite 

 regularly as the plant grew older. Pierre found that the 

 proportion of ash of the colza, (Brassica oleraceaj) dimin- 

 ished in all parts of the plant, (which was examined at five 

 periods,) except in the leaves, in which it increased. 

 (JTahresbericht uber Agriculturchemie, III, p. 122.) The 

 sugar beet, (Bretschneider,) and potato, (Wolff,) exhibit 

 a decrease of the per cent of ash, both in tops and roots. 



In the turnip, examined at four periods, Anderson, 

 (Trans. High, and Ag. Soc., 1859 61, p. 371,) found the 

 following per cent of ash in dry matter : 



July 7. Aug. 11. Sept. 1. Oct. 5. 



Leaves 7.8 20.6 18.8 16.2 



Bulbs 17.7 8.7 10.2 20.9 



In this case, the ash of the leaves increased during about 

 half the period of growth from 7.8 to 20.6, and thence di- 

 minished to 16.2. The ash of the bulbs fluctuated in the re- 

 verse manner, falling from 17.7 to 8.7, then rising again to 

 20.9. 



In general, the proportion of ash of the entire plant 

 diminishes regularly as the plant grows old. 



5. The influence of the soil in causing the proportion of 

 ash of the same kind of plant to vary, is shown in the fol- 

 lowing results, obtained by Wunder, ( Versuchs-Stationen, 

 IV, p. 266,) on turnip bulbs, raised during two successive 

 years, in different soils. 



In sandy soil. In loamy soil. 



1st year. 2dyear. 1st year. 2dyear. 

 Per cent of ash.... 13.9 11.3 9.1 10.9 



6, As might be anticipated, different varieties of the 

 same plant, grown on the same soil, take up different 

 quantities of non-volatile matters. 



In five varieties of potatoes, cultivated in the same soil 



