LIMING THE SOIL. 51 



Rules for Purchasing Lime. 



Large amounts of silica, clay, and other insoluble matter may 

 make it unsafe to buy any kind of lime without first having it 

 analyzed. 



The relative value of the various kinds of lime must be in- 

 versely proportional to the amounts required to neutralize a given 

 weight of acid. Therefore the price of limestone should be less 

 than the price of quick lime in the ratio of 56 to 100; the price of 

 air-slaked lime less in the ratio of 56 to 100; and the price of 

 water-slaked lime less in the ratio of 56 to 74; upon this basis 

 quick lime at $5.00 per ton and ground limestone at $2.80 per 

 ton are relatively proportional in values, if they are all equally 

 pure. 



Freight and hauling are two of the principal items of ex- 

 pense in handling large quantities, and it is a profitable calculation 

 to determine whether quick lime or slaked lime will be cheaper 

 even though purchased at a greater cost per pound of acid neu- 

 tralizing power. And it is well to consider the destructive power 

 of quick lime on the soil and the difficulty in handling. 



It is also true that there are grades of limestone running 

 from 70 per cent to 95 per cent pure, that should effect the price 

 according to quality. 



Generally speaking, the most economic way to buy lime is to 

 get that form which furnishes the greatest amount of basic ma- 

 terial for the least money. It is the calcium and magnesium car- 

 bonate that produces the desired effect in the sail. 



To illustrate this point, let us suppose that ground limestone 

 and quicklime are offered at the same point of shipment at $1.25 

 per ton for the former and $5.00 for the latter. Let us assume 

 that the freight will be $1.50 per ton, and the cost of hauling 

 from the car and spreading $1.00 per ton. Our account will then 

 stand as follows: 



Quicklime Ground stone 

 i ton 2 tons 



Cost at point of shipment $5.00 $2.50 



Freight 1.50 3.00 



Hauling and spreading 1.00 2.00 



Total $7.50 $7.50 



