172 



THE WHEAT CULTTJEIST. 



glassy stem^ is a pretty sure preventive of this evil, 

 whether it be a disease of the plant, or a parasite, or 

 both. We infer that soluble silica, or such sand as forms 

 glass, has much to do in making a bright, glassy straw, 

 for the reason that the ashes of wheat straw yield, on 

 analysis, from 67 to 81 per cent, of silica. As the sand 

 in the soil that furnishes this silica is quite insoluble, 

 unless combined chemically with potash, or soda, or 

 both, we see the great value of salt to yield soda, and 

 of wood-ashes to yield potash, not only for wheat, but 

 for all grasses. By mixing salt with recently-slaked 

 lime, in the proportion of two parts of the latter to one 

 of the former (which should be moistened, and again 

 mixed with muck or mold equal in bulk to the lime), 

 the chlorine in the salt will leave the sodium or soda 

 free, and unite with the lime, forming a soluble salt 

 called chloride of calcium. Being soluble, this salt will 

 supply wheat and other plants with whatever lime and 

 chlorine they may need. In one hundred pounds of 

 common salt there are forty pounds of soda, which, being 

 set free by lime in a moist soil, or compost, will com- 

 bine with silica (silicic acid), and form a soluble salt 

 called silicate of soda. The soluble silicates of soda and 

 potash are partly decomposed in the stems of grasses, 

 leaving insoluble silicates. Leached ashes obtained 

 from plants are made up in a good degree of insoluble 

 silicates of potash, soda, lime, and iron, with a little car- 

 bonic, sulphuric, and phosphoric acids." 



DlTFEEENT KlNDS OF MaNURE AND WhEAT. 



Boussingault, a distinguished agricultural chemist, 

 instituted several interesting experiments to ascertain 



