REASONS OF FERTILITY. 61 



wherever we discover such soils, whether in our own 

 western states, whether on the banks of the Nile or 

 Ganges, in whatever part of the world they may be 

 .ocated, a chemical examination w r ill invariably show 

 the presence of all the substances above named. It 

 is not necessary that they should be in precisely the 

 quantities named here, but they must ail be present. 

 The proportions of some of these may seem so small 

 as to be unimportant; that they are not, will ap- 

 pear when we consider how many hundred pounds 

 there are in an acre of soil twelve inches deep. The 

 smallest of the above proportions would, for an acre, 

 amount to several tons. It would require an im- 

 mensely heavy manuring to add one half of a per 

 cent of any particular ingredient to the soil. 



Unfortunately soils of the first class are not so 

 plenty as those of the second, which bear good crops 

 if an abundance of manure is added. Such are our 

 ordinary soils in all parts of the country. It will be 

 seen that in the column representing the composition 

 of this soil, there are blanks opposite to the potash, 

 soda, and chlorine, denoting that these are absent. 

 Several others, sulphuric and phosphoric acids, and 

 lime, are in much smaller quantities than in the first 

 column. 



In the third column, we find just half of the inor- 

 ganic bodies present in the first entirely wanting, and 

 two others, lime and magnesia, greatly reduced in 

 their proportion. Any ordinary application of manui e 

 would not supply enough to make up all of these 

 deficiencies; and except in places where produce was 

 high and manures cheap, as in the neighborhood of 

 large cities, such land could scarcely be cultivated 

 with profit. We can tell just what is wanting by 

 inspection of the above table; but few farmers could 

 afford to do everything required for the improvement 

 of such a soil at once. The best way weald be to 

 6 



