Explanation of Tables of Analyses 



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

 column are calculated from an actual determination of carbon dioxide (C0 2 ). 

 ( 'alcium or magnesium not in the form of carbonate is present either as hydrated 

 lime (water- or air-slaked), as burned lime (caustic or unslaked), or as basic silicate. 

 All of the products listed in this table have at some time been burned, and the 

 percentage of oxides present as carbonates indicates to what extent the product 

 has absorbed carbon dioxide from the air. 



Tables II and III, "Carbonates of calcium and magnesium." The figures in 

 this column are exclusive of the small amounts of calcium and magnesium com- 

 bined as basic silicates; these are readily soluble in mineral acid solutions but 

 obviously should not be classed as carbonates. 



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

 centage of product that would pass or be retained by the meshed sieves mentioned. 



The limestone products have been published in two groups or grades (see tables 

 II and III) according to fineness of grinding and to conform to definitions voted 

 by the Association of Official Agricultural Chemists at their 1936 meeting. 



Tables I, II, and III, "Neutralizing value expressed in terms of calcium oxide" 

 represents the acid neutralizing value of both the magnesium and the calcium. 

 The figures in the "per cent" column are obtained by a direct titration with stand- 

 ard acid. The "pounds in one ton" are secured by multiplying the figures in the 

 "per cent" column by 20. 



"Insoluble matter" represents material which is insoluble in dilute hydrochloric 

 acid to which a few drops of nitric acid have been added. 



Definitions and Interpretations Relating 

 to Lime Products 



The following definitions and interpretations have been adopted as official by 

 vote of the Association of Official Agricultural Chemists of North America. 



Definitions 



Agricultural liming material is material whose calcium and magnesium 

 content is capable of neutralizing soil acidity. 



Air-slaked lime is a product composed of variant proportions of the oxide, 

 hydroxide and carbonate of calcium, or of calcium and magnesium, and derived 

 from exposure of quick lime. 



Dolomite is a mineral composed chiefly of carbonate of magnesium and calcium 

 in substantially unimolal (1-1.19) proportions. 



Ground limestone (coarse-ground limestone) is the product obtained by 

 grinding either calcareous or dolomitic limestone so that all the material will pass 

 a 10-mesh sieve, and at least fifty per cent (50%) will pass a 100-mesh sieve. 



Ground shells is the product obtained by grinding the shells of mollusks so 

 that not less than fifty per cent (50%) shall pass a 100-mesh sieve. The product 

 shall also carry the name of the mollusk from which said product is made. 



Ground shell marl is the product obtained by grinding natural deposits of 

 shell marl so that at least seventy-five per cent (75%) shall pass a 100-mesh sieve. 



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.) 



High calcic products are materials of which ninety per cent (90%) or more 

 of the calcium and magnesium content consists of calcium oxide. 



High magnesic products are materials in which more than ten per cent (10%) 

 of the total calcium and magnesium oxide consists of magnesium oxide. 



Hydrated or slaked lime is a dry product consisting chiefly of the hydroxide 

 of calcium and oxide-hydroxide of magnesium. 



The word lime when applied to liming materials means either calcium oxide 

 or calcium and magnesium oxides. 



