AGRICULTURAL CHEMISTRY. 87 



yellowisli-red appearance. Where these indications 

 are presented, the land should be thoroughly drained 

 in the first place ; next, the soil should be turned up 

 to the sun and air. Lime should then be applied if 

 it can be obtained at a moderate price, say 20 or 25 

 cents a bushel ; if not, ashes will do very well, but 

 should by no means be applied till the land has becoine 

 dry. Leached ashes for such a purjDose, are worth 

 probably somewhat more than half as much as un- 

 leached. K the ashes were to be applied before the 

 water is removed, the leached would be just about as 

 valuable as the unleached. Neither would be worth 

 much. The potash and soda in the ashes would dis- 

 solve and ran away with the water, and the lime, of 

 which ashes contain some 75 per cent., would lie dor- 

 mant in the soil. 



54. Sesquioxide of Iron (Fe'O^) is composed of 

 the same ingredients as the last, but contains, as the 

 symbols show, a larger proportion of oxygen. The last, 

 as before stated, changes into this, when exposed to the 

 air. The scales and dust abqut the blacksmith's anvil 

 are a mixture of those two oxides. These are a good 

 dressing for fruit trees, but should be applied to the 

 surface, instead of being dug in, in order that the 

 black oxide may be exposed to the air, and thus have 

 an opportunity of being converted into the red, or ses- 

 quioxide. It is this last oxide that gives to many soils 

 their reddish brown color ; and it is one or the other or 

 both of these oxides of iron that give to so many sub- 

 soils their sickly yellow. Such subsoils are both cold 

 and poisonoiLs to plants ; but they need only to be turn- 



