3 



ciency of 16.47 percent calcium oxide and an overrun of only .73 percent in mag- 

 nesium oxide. Apparently this product had through exposure absorbed an un- 

 usually large amount of carbon dioxide which would result in the formation of 

 calcium carbonate, a compound very much lower in calcium oxide than is the 

 average hydrated or slaked lime. 



The Rockland Rockport Lime Co.'s Land Lime was deficient 21.76 percent 

 calcium oxide with an overrun of only 2.47 percent magnesium oxide. See foot- 

 note in table of analyses. 



Lime Definitions 



Reference is made to Massachusetts Control Bulletin Xo. 87, page 9, published 

 in December, 1936, for definitions of Pulverized Limestone (fine-ground lime- 

 stone) and Ground Limestone (coarse-ground limestone) as adopted by the Asso- 

 ciation of Official Agricultural Chemists of North America. The only definition 

 applicable to lime products that has been officially adopted by the Association 

 since 1936 is the following, which was adopted at the 1938 meeting. 



Dolomite. Dolomite is a mineral composed chiefly of carbonate of magnesium 

 and calcium in substantially unimolal (1-1.19) proportions. 



Tonnage of Lime Products Sold in Massachusetts 



Early in 1938 an effort was made to secure reliable statistics as to the tonnage 

 of lime products used in Massachusetts as soil amendments during 1937. Most 

 of the data was supplied by firms selling lime for agricultural purposes in the 

 State. The following summary shows the results of our efforts. 



Tons Sob/ 

 Pulverized and ground limestone .... 34,522 



Hydrated lime ........ 5,271 



Miscellaneous (caustic lime, lime ashes and shell lime) . 284 



Total 40,077 



Explanation of Table 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 sili- 

 cate. 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 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 the various 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 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. 



