of these cases, that the total amount of calcium oxide in every form 

 of lime should be the first consideration when purchasing any of these 

 materials. Other rules for making a choice depend upon conditions 

 which are discussed below. Eelative money values can be determined 

 at any time from the foregoing explanation of relationship between 

 the different lime- materials. It must also be remembered in that 

 connection, however, that the cost of handing larger quantities and 

 the additional freight rates involved must always be taken into con- 

 sideration in calculating the actual and relative cost of the different 

 materials. The prices for lime vary in this state, in the knowledge 

 of the writer, from $2 per ton up to $15 per ton, and there seems 

 to have been no uniformity of price based on actual lime content or 

 on fineness of division. Local circumstances of a variety of kinds 

 have usually set the prices. Ground limestone and sugar-house refuse 

 lime have been selling at rates varying from $3.50 to $6.50 per ton, 

 and, in most cases, very little of the other forms of lime is available 

 on the market for agricultural uses. A list of some of the principal 

 firms which engage in selling lime in different forms may be obtained 

 by addressing the Division of Soil Chemistry and Bacteriology. 



The following is a consideration of the function of lime materials 

 in soils : 



1. Lime materials have the power of improving the crumb- 

 structure of clay and making it more pervious to water and air, by 

 making a large number of soil crumbs from large sticky masses. 

 Therefore, lime makes clays and clay adobe soils looser, tends to 

 prevent packing, baking, and cracking, makes plowing and cultivating 

 easier, and, in general, makes the soil, physically, a healthier medium 

 for plant growth. 



2. Lime materials (as above described) serve as a source of the 

 element calcium to plants. Calcium is one of the ten essential chem- 

 ical elements in plant growth. 



3. Lime materials tend to make "sour" soils "sweet." Speaking 

 correctly, they tend to change an acid soil condition to a less acid one. 

 Acidity of soils may be very detrimental to the growth of many 

 agricultural crops. 



4. Lime materials are necessary for useful and beneficial bacteria 

 and other microorganisms of the soil. It furnishes these the element 

 calcium, whicli is as essential to them as to the higher plants. It 

 promotes a slightly alkaline condition, which is probably ideal for 



