1G4 ON THE USE OF 



Art. XXXVIII.— the USE OF SUPERPHOSPHATE OF LIME, 

 PRODUCED WITH ACID AND BONES FOR MANURE. 



Prize Essat of the R. A. S. E. 



By Mr. W. C. Spooner. 



[This very valuable Essay commences with some preliminary remarks 

 on the necessity of raising the largest crops of roots at the least possible 

 expense, and on the proved superior economy in the employment, with 

 that object, of bones mixed with an acid over that of bones alone. The 

 Author then proceeds : — ] 



The specific effect of Lone as food for tLe tnrnip-crop lias 

 long' been known — long-, indeed, before science was in a 

 position to explain tbe cause of its peculiar effects, or to 

 assign correctly to wliat portion of its constituents the bene- 

 fits are chiefly due. 



It was found, greatly to the surprise of many, that burnt 

 bones, in which of course the organic parts had been de- 

 stroyed, were equal, if not superior, in their effect to bones 

 not so treated ; and that when boiled, in which state the fat 

 had been expelled, they were more productive than bones in a 

 fresh state. It was thence supposed by those Avho jumped 

 to conclusions too hastily, that the substances thus expelled 

 were useless, at an}- rate for the turnip-crop, and they were 

 apparently supported by the theory of a very eminent 

 chemist, who, if we mistake not, laid it down as his opinion 

 that the value of manures depended principally, if not en- 

 tirely, on their inorganic ingredients — a doctrine altogether 

 at variance with the previous generally received notions, that 

 ammonia was the true fertilizing element, and that its amount 

 afforded the measure of the value of manure. In medio 

 tutissrimis ibis — the truth, we take it, will be found to lie 

 between the two extremes. We may justly regard the 

 inorganic constituents as being the most important and 

 essential portion of manure, affording to the plant what the 

 skeleton does to the animal, the basis of support; and, as 

 plants can obtain no other supply but through the soil, 

 we may justly regard them as the most essential consti- 

 tuents. 



The other elements are, to a great extent, supplied through 



