192 MAINE AGRICULTURAL EXPERIMENT STATION. I916. 



LIME, LIMESTONE, AND GYPSUM. 



Agricultural lime, limestone and gypsum depend for their 

 agricultural value largely upon the lime which they carry and 

 their freedom, from other impurities. Lime in limestone exists 

 as calcium carbonate. When this is burned carbon dioxide is 

 driven off and lime or quick lime (calcium oxide) remains. 

 When exposed to moisture this takes up water and becomes 

 slaked or calcium hydrate. If this material is continued to be 

 exposed to the air it again takes on carbon dioxide from the air 

 and comes back to calcium carbonate similar in chemical com- 

 position to the limerock from which it is made, but differing 

 very materially in its mechanical condition. 



No. 3730, R-R Land Lime, made by the Rockland-Rockport 

 Lime Co., Rockland, Me., guaranteed to contain 60 to 65 pei 

 cent of total lime (calcium oxide) was sampled at Kendall & 

 Whitney's, Portland. It was found to carry 64.08 per cent of 

 lime (calcium oxide) and 3.25 per cent of insoluble matter. 



No. 3786, R-R Land Lime, made by the Rockland-Rockport 

 Lime Co., Rockland, Me., guaranteed to contain 60 to 65 per 

 cent of total lime, was sampled at R. B. Dunning & Company's, 

 Bangor, and was found to carry 61.12 per cent of lime (calcium 

 oxide) and 5.08 per cent of insoluble matter. 



No. 4010, Pulverized Agricultural Limestone, Dudswell 

 Brand, made by the Dominion Lime Co., Sherbrook, Quebec, 

 guaranteed to carry 52 to 55 per cent of lime, was sampled at 

 the Farmers' Union Storehouse, Lee. It was found to carry 

 53.48 per cent of lime (calcium oxide) and 4.08 per cent of 

 insoluble matter. 



No. 4142, Pulverized Agricultural Limestone, Dudswell 

 Brand, made by the Dominion Lime Co., Sherbrook, Quebec, 

 was guaranteed to carry from 52 to 55 per cent of lime. Sam- 

 ple was taken at N. E. Curtis', Bowdoin, and was found to 

 carry 53.44 per cent of lime (calcium oxide) and 7.03 per cent 

 of insoluble matter. 



No. 4109, Agricultural Pownal Limestone, Fine Ground 

 Limestone, made by the Pownal Lime Co., North Pownal, Vt, 

 was guaranteed to carry 45 to 50 per cent of lime. The sample 

 was taken at the Gait Block Storehouse, Portland, and found to 



