AGRICULTURAL LIME 



101 



lime, or calcium hydroxide, contains only 1513 pounds of 

 calcium oxide, the remaining 487 pounds consisting of 

 water, and a ton of air-slaked lime, or calcium carbonate, 

 contains only 1120 pounds of calcium oxide, the remaining 

 880 pounds being composed of carbon dioxide, while quick- 

 lime should be pure calcium oxide. On this basis of com- 

 parison, we see that it is much more expensive to freight 

 a given amount of calcium in the carbonate or hydroxide 

 form than in the oxide form. In shipping, it is necessary 

 that the quicklime and water-slaked lime be barreled or 

 sacked, because by exposure to moisture and air both of 

 these materials are transformed into air-slaked lime, and 

 also on account of the difficulty of loading and unloading 

 these caustic materials. The air-slaked lime, or ground 

 limestone rock, which are each calcium carbonate, and 

 not caustic, may be handled without containers. 



The same condition holds for hauling the different 

 forms of lime from the railroad station to the farm that 

 held in the freight charges. It is most economical to haul 

 the quicklime, the water-slaked costing somewhat more, 

 and the carbonate of lime is most expensive for cartage, 

 though the carbonate is the most easily handled. A smaller 

 application of caustic lime will produce more marked 

 effects than will a larger application of carbonate of lime, 

 although the latter is more lasting in its influences. The 

 amounts of other forms of lime which are equivalent to a 

 ton of quicklime are given in Table XII. 



TABLE XII 



77. Applying Lime to the Soil. Some difficulty attends 

 the distribution of quicklime on the soil, for it is necessary 



