92 



AGRICULTURE. 



from i to 4 per cent, of phosphates, and from 

 30 to 40 per cent, of calcium carbonate. Good 

 wood ashes not only furnish available plant-food, 

 but improve the physical condition of the soil. 

 Coal ashes are of no use as a fertilizer. 



(4) TABLE I. 



SHOWING THE COMPOSITION OF SOME OF THE 



PRINCIPAL COMMERCIAL FERTILIZING MATERIALS.* 



The above table shows the comparative 

 values of the most important commercial fertil- 

 izers as food for plants. The amount of these 



* Adapted from Year-book, 1902, p. 571. 



