furnish the ground limestone or coarse-ground product. The finer an unburned 

 limestone or shell lime is ground, the more rapidly will it become effective in 

 neutralizing soil acidity and in furnishing calcium and magnesium to growing 

 plants. 



Eight brands out of a total of 29 showed deficiencies in either calcium or 

 magnesium oxide: five of these brands had a sufficient overrun in the other 

 ingredient so that no deficiency in calcium oxide equivalent was noted. Three 

 brands showed net deficiencies in calcium oxide equivalent as follows: 



Brewer & Co., Snow Fluff Agricultural Hydrate .... 3.08% 



H. E. Millard, Sweet Arrow Hydrated Lime 4.73% 



United States Gypsum Co., Red Top Hydrated Lime . . 4.05% 



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 (C0 2 ). 

 Calcium 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 proportion of oxides present as carbonates indicates to what extent the 

 product has absorbed carbonic acid from the air. 



Tables II and 111, "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 the various meshed sieves mentioned. 



Tables I and 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 "percent" column are obtained by a direct titration 

 with standard acid. The "pounds in one ton" are secured by multiplying the 

 figures in the "percent" 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. 



The figures in parenthesis following the brand name show the number of 

 samples collected and analyzed. 



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