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plant does not under certain circumstances 

 take more or less quantity of salts, or that cer- 

 tain salts are not substituted for others; as 

 instance, Soda for potassa, &c., no; but it is 

 certain that when a plant finds in the soil 

 those substances which predominate in its 

 ashes, it prospers much better and yields 

 more abundant harvests. 



The exact analyses of the ashes of plants, 

 must determine which of the mineral manures 

 are most favourable to their growth and exis- 

 tence. Many chemists have been occupied 

 upon these analyses, and we give a synopsis 

 of their labours in tabular form, on page 25. 



In examining the tables, it will be ob- 

 served that there is a striking similarity in 

 the principal results, although the plants 

 analyzed came from soils of different composi- 

 tions. Thus, it is seen that the ashes of clo- 

 ver always contain a considerable proportion 

 of carbonate of lime, and herein is explained 

 the efficacy of plaster or lime in the culture 

 of those plants. The ashes of potatoes, of Je- 

 rusalem artichokes, of kidney and common 

 beans contain fifty per cent, and more of potas- 

 sa; the ashes of wheat give proportionally 



