234 



LIMB-PLANTS. 



latter contain a very much larger amount of lime and 

 potash than the former, and for this reason they have 

 very properly been denominated lime-plants. It will 

 be seen also, from their composition, that phosphoric 

 acid forms an important ingredient in them, while the 

 silica is very small, comparatively. The removal of a 

 clover crop, therefore, without applying suitable ma- 

 nures, will exhaust the soil quite as much as a crop of 

 the cultivated grasses, though of different constituents. 

 A soil, to bear good clover crops, requires a considerar 

 ble ingredient of lime, potash, and phosphates, and with- 

 out the application of these manures in some form or 

 other they will inevitably run out. Plaster of Paris, 

 lime, and ashes leached and unleached, applied to clover 

 soils, are always followed with good effectSi 



Table XI. — Analysis op Specimens op Weeds, as 



TAKEN PEGM THE FIELD, AND WHEN DRIED. 



If now we cast our eye at the analyses of some of 

 onr common weeds, we shall see how far superior the 

 cultivated grasses are in nitrogenous or nutritive prin- 

 ciples. 



The albuminous principles are very much less than 

 in either the natural or the artificial grasses. 



