PHOSPHATE OF LIME. 105 



Phosphate of lime, consisting of lime 65 parts, 

 and phosphoric acid 45 parts, enters largely 

 into the structure of turnips, wheat, and many 

 other crops. It occurs in many composite 

 rocks, and it exists in its native state in Corn- 

 wall, in the north of England, and Spain, and 

 is known by the name of Apatite; in the latter 

 country it is abundantly present in Estrema- 

 dura, where it is so common, that the divisions 

 of the fields are said to be formed of it. In this 

 state, however, it has never been used as a ma- 

 nure, we are therefore unable to speak positive- 

 ly as to its value; but reasoning from analogy, 

 from the beneficial effect that this substance 

 produces in the state of bone dust, there can be 

 little doubt but that its use would prove highly 

 advantageous. 



The chief source of this manure in this coun- 

 try arises from the use of bones; the beneficial 

 effects of which are attributed almost entirely 

 to the phosphate of lime they contain. In their 

 analysis, calcined bones yield between fifty and 

 sixty per cent of* this earth, and when it is 

 found that phosphate of lime exists in almost 

 every part of the grass tribe, in the seed, tho 

 bran and the stem, there is every reason to 

 believe that this is the fertilizing property; 

 and added to this, we have the fact before us, 

 that bones, whether used fresh from the slaugh- 

 ter-house, without having been subjected to 

 any calcining process, whether taken from the 

 kitchen after having been either boiled or 

 roasted, or from the manufactory, where every 

 portion of oil or fatty matter is extracted, or 

 from caves, or other existing deposites of bones, 



10* 



