I'HOSPHATliS 



71 



Classification of Phosphates. — From the foregoing it is shown 

 that there are three classes of phosphates used for fertiHzing 

 purposes. 



( Raw bone-meal 



Bone phosphates 



Steamed bone-meal 

 Bone-black 

 Bone-ash 

 Bone tankage 

 Dry ground fish 



Florida \ 



South Carolina 



Rock phosphates { 



Tennessee 



Land pebble 

 River pebble 

 Hard rock 



Land rock 

 River rock 



Brown rock 

 Blue rock 

 White rock 



Apatite 



Rodunda phosphate 

 [ Phosphatic guanos. 



3. Basic slag phosphates. 



(3f the bone phosphates, bone-ash is not found much on the 



Fig. 8.— The hog; one of the sources of bone phosphate. — Courtesy of the 

 Wisconsin Exp. Station. 



American market and bone-black is usually acidulated (treated 



