230 AMERICAN AGRICULTURE. 



from the dry season." The kind of soil, and the circum- 

 ctances attending the application are not stated, but we infer 

 from the product on the ground, that it was a very thin and 

 light, and probably a dry soil. 



The observation has been frequently made in this country, 

 that certain half-cleared pastures, where the trees and brush 

 had been prostrated and partially burnt, leaving a heavy 

 covering of old logs and dead branches, gave a much larger 

 supply of feed than such as had been entirely cleared. But 

 all the facts and attending circumstances have not been given 

 with suinVient particularity to draw any well settled conclu- 

 sions ; yet from the generality of the remark by observing 

 and careful men, there is undoubtedly some weight due to it. 

 The same effect has been often claimed from certain stony 

 fields, which apparently give much larger returns than others 

 from which the stones had been removed. If the results are 

 as have been inferred, after deducting something for what 

 observation or science may possibly not yet have detected, 

 we Avould ascribe them to two causes. 1. The gradual de- 

 composition of the vegetable covering and stone, and the di- 

 rect food which they thus yield to the crop ; and 2. the 

 greater and more prolonged deposit of dew, which is going 

 forward through most of the 24 hours of every day on larger 

 portions of the field. Does the influence of the shade and 

 moisture promote an unusual deposite of ammonia, nitric acid, 

 or any of the fertilizing gases ? We are inclined to think 

 nitric acid is thus formed in considerable quantities,, and es- 

 pecially where there is an appreciable quantity of lime in the 

 soil. Both M. Longchamp and Dr. John Davy assert, "that 

 the presence of azotised matter is not essential for the genera- 

 tion of nitric acid or nitrous salts, but that the oxygen and 

 azote of the atmosphere when condensed by capillarity, will 

 combine in such proportions as to form nitric acid thrugh the 

 agency of moisture and of neutralising bases, such as lime, 

 magnesia, potash or soda." (lire.) The condition of the 

 soil is precisely analogous to the artificial nitre beds, deduct- 

 ing their excess of manure and calcareous matter. These 

 exist to some extent in every soil, and it is probable under 

 similar circumstances they will produce an amount of nitric 

 acid proportionate to their own quantity, which in every case 

 will be particularly felt by the crops. We have the shade, 

 moisture, and capillary condition similar to those of the nitric 

 beds, for the formation and condensing of the acid, which in 

 this instance, is washed down into the soil by every succes- 



