PHOSPHORUS. 51 



of phosphoric acid and three equivalents of lime, 

 and contains, in 100 parts, phosphoric acid 45.81, 

 lime 54.19. This is the state in which this salt 

 is naturally found in bones, coprolites, phos- 

 phorite, apatite, etc. 



Neutral Phosphate of Lime contains two 

 equivalents of lime, one of water, and one of 

 phosphoric acid; in 100 parts, phosphoric acid 

 52.20 ? lime 41.18, water 6.62. 



Superphosphate of Lime, termed also acid 

 and bi--pliosphate of lime, contains one equiva- 

 lent of phosphoric acid, one equivalent of lime, 

 and two equivalents of water ; containing, in 100 

 parts, phosphoric acid 60.69, lime 23.93, water 

 15.38. If we remove from bone-phosphate of 

 lime the three equivalents of its base, and re- 

 place them with water, we obtain tri-basic phos- 

 phoric acid, usually in the form of a colorless, 

 syrupy liquid, very acid to the taste. Again, 

 if we remove from bone-phosphate of lime but 

 two equivalents of lime, and replace them with 

 water, we obtain super pi losphate of lime. This 

 change, in either case, can be effected by sul- 

 phuric acid. This acid, having a greater affinity 

 for the lime than phosphoric acid has, unites 

 with the lime, forming gypsum or land plaster. 

 Superphosphate of lime forms white scales, 

 which are very soluble in water, imparting to it 

 an acid taste. 



