112 



INORGANIC CONSTITUENTS OF PLANTS. 



Magnesium (Mg.) combined with oxygen forming magnesia. 

 Aluminum (AL) ...... oxygen ... alumina. 



Silica (Si.) ...... oxygen ... silica. 



Iron (Fe.) ) (oxides 



Manganese (Mn.)> ...... S^ '" 1 and 



Copper (Cu.) j sulphur - (sulphurets. 



222. The quantity of inorganic matter or ash left by plants, varies 

 in different species, and in different parts of the same plant. The 

 dried leaves usually contain a large quantity. Saussure found that 



Dried bark of Oak gave ...................................... 60 of ash in 1000 



Dried leaves ............................................... 53 



Dried Alburnum ............................................... 4 ...... 



Dried duramen ................................................. 2 



The dried leaves of Elm contain more than 11 per cent, of inorganic 

 matter, while the wood contains less than 2 per cent. ; the leaves of 

 the Willow, 8 per cent., wood, 0*45 ; leaves of Beech, 6'69, wood, 

 0'36; leaves of Pitch-pine, 3'5, wood, 0*25. Thus, the decaying 

 leaves of trees restore a large quantity of inorganic matter to the soil. 



223. The following tables show the relative proportion of inorganic 

 compounds present in the ash of plants: 



According to Sprengel, 1000 Ibs. of wheat leave 11 '77 Ibs., and of wheat 

 straw 35-18 Ibs. of ash, consisting of 



Grain. Straw. 



Potash .......................................... 2-25 ......... 0"20 



Soda ............................................. 2-40 ......... 0-29 



Lime .......................................... 0-96 ......... 2-40 



Magnesia ..................................... 0'90 ......... 0*32 



Alumina with trace of iron ............... 0-26 ......... 0'90 



Silica ............................................. 4-00 ......... 28-70 



Sulphuric acid ................................. 0-50 ......... 0'37 



Phosphoric acid ............................. 0-40 ......... 1-70 



Chlorine ........................................ 0-10 ......... 0-30 



11-77 Ibs. 35-1 8 Ibs. 



In 1000 Ibs. of the grain of the Oat, are contained 25 - 80 Ibs., and of the dry 



straw 57 '40 Ibs. of inorganic matter, consisting of 



Grain. Straw. 



Potash ......................................... 1-50 ......... 8-70 



Soda ........................................... 1-32 ......... 0-02 



Lime ............................................. 0'86 ......... 1-52 



Magnesia ....................................... - 67 ......... 0-22 



Alumina ...................................... . 0'14 ......... 0'06 



Oxide of iron .................................. 0-40 ......... 0'02 



Oxide of manganese ........................ O'OO ......... 0-02 



Silica ............................................. 19-76 ......... 45-8S 



Sulphuric acid ................................ 0'35 ......... 079 



Phosphoric acid ............................... 0'70 ......... 0'12 



Chlorine ........................................ 0-10 ......... 0-05 



57-40 Ibs. 



