Quicklime, burned lime, caustic lime, lump lime, unslaked lime, are liming 

 materials that have a high content *f calcium oxide, with magnesium oxide, 

 produced by heating suitable carbonates until substantially all the carbon 

 dioxide has been eliminated. 



Hydrated or slaked lime is the product obtained by treating quicklime 

 with sufficient water or steam to combine with its oxides. 



Air-slaked lime is the product obtained by exposing quicklime or hydrated 

 lime to the atmosphere until partially carbonated. 



Ground limestone is the product obtamed by grinding calcareous or 

 dolomitic limestone. Not less than seventy-five per cent (75%) shall pass a 

 100-mesh sieve. It shall contain calcium and magnesium carbonates equiv- 

 alent to not less than ninety per cent (90%) of calcium carbonate. 



Ground shell lime is the product obtained by grinding the shells of mollusks. 

 Not less than seventy-five per cent (75%) shall pass a 100-mesh sieve. It 

 shall contain calcium and magnesium carbonates equivalent to not less than 

 eighty per cent (80%) of calcium carbonate. 



Marl, ground shell marl, is the product obtained by grinding natural 

 deposits of shell marl. Not less than seventy-five per cent (75%) shall pass a 

 100-mesh sieve. It shall contain calcium and magnesium carbonates equiv- 

 alent to not less than eighty per cent (80%) of calcium carbonate. 



Waste lime, by-product lime, is any industrial waste or by-product con- 

 taining calcium or calcium and magnesium in forms that will neutralize acids. 

 It may be designated by the prefixation of the name of the industry or process 

 by which it is produced, i.e., gas-house lime, tanners' lime, acetylene lime- 

 waste, lime-kiln ashes, calcium silicate, etc. 



Gypsum, land plaster, or crude calcium sulfate, are products consisting 

 chiefly of calcium sulfate. They may contain twenty per cent (20%) of 

 combined water. (They do not neutralize acid soils.) 



Explanation of Tables of Analyses. 



Table I, "Proportion of total oxides as carbonates." The data furnished in 

 this column are calculated from an actual determination of carbon dioxide 

 (C02). Calcium or magnesium not in the form of carbonate is present either 

 as hydrated lime (water- or air-slaked) or as burned lime (caustic or unslaked). 

 It should be understood that all of the products listed in this table have at 

 some time been burned, and the proportion of oxides present as carbonates 

 indicates to what extent the product has absorbed carbonic acid from the air. 



"Pounds of effective oxides in one ton" represents the sum of the calcium 

 and magnesium oxides in one ton of the lime product, assuming that both 

 ingredients from this source will become readily available. 



The calculations found in column "Cost of 100 pounds of effective oxides" 

 are based on prices furnished by the producers. 



Table II, "Pounds of effective oxides in one ton." In securing these data 

 the degree of fineness to which the limestone has been ground is taken into 

 consideration. On those products which are finely ground so that all of the 

 material will pass through a 20-mesh sieve, it is assumed that all of the calcium 

 and magnesium oxides will become available in the soil within a five-year 

 period. On those products which will not wholly pass a 20-mesh sieve, it is 

 assumed that the oxides in that portion which is coarser than 20-mesh will be 

 only 50 per cent effective during the same period. 



Under "Mechanical analysis" the figures represent in round numbers the 

 percentage of product that would pass the various meshed sieves mentioned. 



In both tables the figures in parenthesis following the brand name show the 

 number of samples collected and analyzed. 



