COM Ml \l* I \l. 1 1 Kill 



111 



phate is now placed in sacks and sold as acid PHOS- 

 PHATE, DISSOLVED BONE, DISSOLVED KOCK, etc. 



There ire three kinds of phosphorus compounds in 

 acid phosphate, tad they are known as: (1) Soluble 

 phosphoric acid/ which is easily soluble in water; 

 (.) reverted phosphoric acid, which is easily 

 soluble in weak acids, such as are found in the soil; 

 (3) INSOU r.u: PHOSPHORIC ACID, which is soluble in 

 strong acids. The insoluble phosphoric acid is part 

 of the original ground rock which has not been acted 

 on by acids; it forms but a very small part of good 

 fertilizers, seldom above 1 per cent. The soluble and 

 ted phosphoric acids are classed together as avail- 

 able phosphoric acid. The sum of the available and 

 insoluble gives what is called the total PHOSPHORIC 



ACID. 



135. Bone Phosphate. — The bones of all animals 

 contain large amounts of phosphate of lime, and are 

 much used for fertilizers. When the bones are simply 

 ground and sold for a fertilizer the product is known 

 as raw bone, and nearly all of the phosphoric acid it 

 contains is insoluble. The steamed bone, while it is 

 made up principally of insoluble phosphoric acid, de- 

 cays much more rapidly in the soil, and for this r 

 is of more value as i fertiliser. A- i large part of the 

 organic matter has been removed by the process of 

 cooking, steamed hour containj more phosphoric seid 



than raw bone. Haw hone Contain! 



of phosphoric seid, or Lfl to M per cenl ol bone phos- 

 phate. Steamed bone contains 22 to 29 per cent of 

 phosphoric acid, or 48 to 63 per cent of bone phosphate. 



