FARM EXPERIMENTS AT LAKESIDE. 131 



nures, as produced at my farm, held of fertilizing 

 substances nearly two and a half times as much in 

 the cord as was found in those obtained from stable 

 vaults in the city. 



It is of the highest consequence in successful 

 farming that the actual quality of fertilizing agents 

 be considered, rather than appearances, bulk, or 

 color. Every substance that holds potash, phos- 

 phoric acid, lime, soda, and the nitrogenous bodies, 

 has value, and the value depends upon the amount 

 and the condition in which these agents exist in the 

 substance. If we can know what is the exact value 

 of the agent we are using, we can experiment un- 

 derstandingly and successfully ; but if we are at 

 work in the dark, our results will be wholly unre- 

 liable and valueless. 



The results of our experiments have established 

 this point clearly, that in order to .grow crops suc- 

 cessfully, all the substances needed by plants must 

 be present in the soil in which they flourish. The 

 soils of cultivable lands hold in a greater or less 

 proportion all that is essential to the growth of 

 plants. Sometimes one or more of these essentials 

 is largely in excess, or there is more than is needed 

 by any crop for a succession of years; and often 

 one or more are held in small amount, barely suffi- 

 cient for some crops and wholly insufficient for oth- 

 ers. A soil resulting exclusively from the disin- 



