7 8 



PLANT PRODUCTS 



are all cases of reversible reaction, that the extraction with 

 weak solvents is some kind of analogue to the life of the plant. 

 The complete analysis of soils is given in many text-books, 

 but only one or two illustrations can be found room for here. 

 Whatever part of the world soils come from, there is some 

 kind of resemblance. The following table, taken from a 

 book by the author, gives the composition of a few Indian 

 soils, to which have been appended one or two analyses from 

 Northumberland. 



TABLE 13. 



To interpret any soil analysis the most important points 

 to consider are the following. Sand and insoluble silicates 

 often give a clue to the physical condition of the soil. 

 L,uxmore showed the correlation between insoluble silicates 



