SUPERPHOSPHATE OF LIME 

 [First printed in the Country Gentleman in March, 1853.] 



This manure, suggested by Baron Liebig about ten years 

 since, has come into very extensive use in England, and, from 

 present indications, will soon figure very largely in American 

 husbandry. It is unnecessary here to allude to the success 

 that has attended its application, as agricultural readers well 

 know. 



The enterprising farmer who proposes to himself its use, 

 naturally inquires whether it is cheaper to manufacture it on 

 his own premises, or to purchase it. 



To assist in answering this question, I shall give the results 



of analyses of two articles now in market, namely: "M 's" 



and^'D 's." 



It will be best to examine to some extent the chemistry of 

 the subject, in order to understand what constitutes the value 

 of Superphosphate of Lime. 



There are two compounds of lime and phosphoric acid, 

 which are of agricultural interest, viz., the neutral phosphate, 

 which we shall call simply phosphate; and the super-phos- 

 phate. The first, when pure, contains in 100 parts — Phos- 

 phoric acid, 48^2 5 Lime, Sli/o. 



It is the chief earthy ingredient of bones, and that to which 

 they mainly owe their efficacy as a manure. It is well knoA\Ti, 

 that although bones are highly useful when applied to the 

 soil in an unbroken state, they become far more valuable if 

 reduced to small fragments, or better still if ground to dust. 

 This is because nothing can enter the plant in a solid form. 

 All that a crop absorbs through its roots, must be dissolved 

 in water. The phosphate of lime, as it occurs in bones, is 

 only very slightly soluble in water, and is of course very 

 slowly presented to the plant. The more finely it is divided. 



