13i Eepokt of Farmers' Institutes 



RELATIVE EFFICIENCY OF CARBONATE OF LIME OF VARIOUS 



DEGREES OF FINENESS 



W. H. MacIntire 



INTRODUCTION 



In the art of agriculture, the use of lime for soil improvement 

 constitutes a practice which has been followed since ancient time. 

 However, in spite of this long usage, relatively little advance has 

 been made scientifically in the simplification of lime problems. 

 Particularly is this true in regard to studies as to differential 

 values between lime carbonate of various degrees of fineness. As 

 an instance in point, the chemical composition of limestone and 

 the chemistrv of its burning were not known until about 1800. 



In so far as we know, the custom of burning lime for building 

 purposes antedated the practice of its agricultural use. It was, 

 therefore, known that by burning, the hard limestones could be 

 made utilizable as well as the soft chalks, marl and ashes, which 

 were probably first used for agricultural purposes. Agriculturally 

 speaking, then, the practice of burning was followed primarily 

 to permit utilization of limestone, especially the harder rocks, by 

 effecting a state of fineness which would permit of its application 

 to the soil. 



It is our purpose, in submitting this paper, to enter into a con- 

 sideration of some of the chemical activities which are character- 

 istic of the various forms of lime. It is not our intention to 

 dwell upon the biological phase of the soil needs for lime, nor to 

 any extent upon the comparative physical effects of liming, but 

 rather upon the chemical activities of the carbonate forms in 

 the soil. 



At this point, let it also be understood that we have no inten- 

 tion of entering the field of economics of the use of lime in its 

 various forms, under such conditions as exist in the state of Xew 

 York. A study of Circular No. 7 of the Cornell Station will 

 show that the cost problems are well understood and ably handled 

 by the extension service of Cornell University. Furthermore, 

 the problems with which we are familiar in our own state may be 

 verv different from those of vour state. Over vast areas in 

 Tennessee, we have underlying limerock. The crusher often goes 

 to the farmer and his limestone comes from his own farm. Tran- 



