418 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



water now upon this globe as there was at the time of Noah's 

 flood ; and if the earth be dry, the atmosphere must contain the 

 moisture ; it may be in the form of dew or vapor, but water is 

 there, and so long as we can present colder surfaces, that deposit 

 of moisture is going on. The amount of ammonia received upon 

 an acre of land when it is properly sub-soiled and underdrained 

 is many times as great as that contained in the amount of Peru- 

 vian guano usually applied to an acre of land. It is fifteen times 

 as great as that contained in a usual dose of stable manure 

 applied to an acre of laud. This is not the case when the drain 

 is shut at the lower or upper end, but when a drain is properly 

 arranged, the whole land is charged with ammonia. At the same 

 time it is true that if the plowing is only eight inches deep, you 

 may not get ammonia enough to give to the moisture in the soil 

 the power to change the condition of inorganic matter. 



Every farmer knows that by leaving an acre of soil in naked 

 fallow for a certain length of time, and disturbing its surface 

 occasionally he can enrich it, and it will afterward bear crops 

 which it would not before. Why ? Has he added anything to 

 it ? No. Has he taken anything from it ? No. What then ? 

 Why, the condition of the constituents of that soil has in a 

 degree been changed, and therefore the potash which was con- 

 tained simply in particles of feldspar, and the phosphate which 

 was merely there as phosphatic rock have undergone a certain 

 alteration of condition, and are rendered capable of being dis- 

 solved by coming in contact with proximates, which, by capil- 

 lary attraction, traveled upon the moist surfaces of the soil. 

 But he does another thing; he raises crops, and when the roots 

 have penetrated into the sub-soil, and have taken up inorganic 

 matter therefrom, he plows those crops under. In analyzing 

 these there is nothing new found, but they have altered the con- 

 ditions of the constituents appropriated ; the potash is altered, 

 and has new functions. It has grown capable of combining with 

 silex to give strength to the straw of the grain. There was silex 

 enough in the soil for a million crops, but it was not in a proper 

 condition. When in another lecture I shall speak of potash as 

 a fertilizer, this may be more fully explained ; but it must now 

 be evident to you that a soil though barren, may have chemi- 

 cally the same constituents and in the same relative proportion 

 as one that is fertile. Then there must be a difference other 

 than in the relative quantity of the constituents. 



